I frequently see people suggesting the use of Breath of the Dying weapons berserker axes for Zeal Paladins, charge paladins, some Barbarians, whatnot. They usually say that it's for the damage. Now, Berserker axes, as one-handed weapons, don't benefit nearly as much from +400% damage as from +400 damage (given their regular maximum damage is 71). Understandably, Breath of the Dying has some other benefits (Indestructible, making costs more manageable, Poison Nova can be fun, etc.). At the same time, however, most of these benefits don't much matter:
50% Chance to Cast Level 20 Poison Nova When You Kill An Enemy: Besides being a ridiculously long name for a mod, there are also a few problems with this. The first of which is the fact that you cannot boost synergies or give it bonuses from items that increase skill level. Its damage is more or less locked in ... at 356-390. Unless you want to blow your glove slot on Trang's gloves, you'll be throwing down a worthless few hundred poison damage before resistance. Once resistance factors in, this damage is much less. And it'll basically never apply in PvP since most people don't even bother reviving their mercenaries, and killing random enemies in the Blood Moor and leaving yourself open to attack in order to inflict about one-hundred or so damage at most (since everyone will have 75% resistance or higher unless they're a glass cannon, in which case, you shouldn't be wasting your time trying to inflict damage with Poison Nova; you should just move in and kill them and their sacrificed life total and defense in one hit).
Indestructible: This saves you money. If you've ever gone out and killed anything in Hell, ever, you know how easy it is to make money. And, if you use your character in PvP and don't want to risk losing money all the time when you die by keeping a bunch on you and in your stash, keep it on another character and transfer some over every now and then. This should never be what sells you on a weapon. The final argument to be made for Indestructible is this one: Ethereal. Ethereal weapons get even more damage. And, yes, your maximum damage will be higher, but your average damage (without counting in skills, or anything else) will actually be 100 lower on an Ethereal Breath of the Dying Berserker Axe than on a (regular, much easier to find, much less expensive in terms of high runes) Grief Berserker Axe.
60% Increased Attack Speed: Grief has 30-40%, making it quite a shame that it's so easy to get it elsewhere, especially for paladins intending to use Fanaticism, since it means Grief users hit the lowest frames per attack fairly easily.
400% Enhanced Damage: This gives less of a return than Grief on a Berserker axe, meaning you get much less damage once skill damage multiplications factor in. Also, Grief is just as good in a Phase Blade in terms of damage amplification as in a Berserker axe, and at -30 speed instead of 0 (essentially 30% IAS).
Increased Damage Against Undead: Since most characters are made to either find magic items, be able to solo uber Tristram, or to pk or pvp, and since melee characters tend to make terrible magic finders, and since even if they wanted to perform such a role, most bosses worth killing are demons, this is a worthless ability. Sure, there are lots of undead in uber Tristram, but most successful Tristers will simply wipe out the demons without bothering with the minions and while avoiding as many as possible anyway. And in PvP, the only use it would have is against skeletons, who are pretty weak and really just make you lag so the necromancer can kill you through another means.
-25% Target's Defense: this is decent, but its function against Champions, Uniques, and Bosses is halved. It's far from essential, especially considering that most melee characters concerned with attack rating will use Angelic items for massive attack rating. Oh, and did I mention that Grief has this too?
+50 Attack Rating: ... Right, and angelic items add like 1188. Let's move on...
+50 Attack Rating against Undead: ... So it's negligible and less often applicable as well?
7% Mana Stolen: This is alright, I won't lie. Even after you factor in that you only get a fraction of the return in Hell mode.
12-15% Life Stolen: This is pretty decent.
Prevent Monster Heal: This mod doesn't work on bosses or players.
+30 to all attributes: This is pretty much the shining ability of this runeword, in my opinion, and it's not even amazing. It gives you some life, mana, damage, and a very minor amount of defense and helps you improve your block. Of course, that 30% extra damage still won't make up for the lost damage compared to a Grief; the life is good, but it's only a couple hundred even on a barbarian (4 hit points per vitality point) using battle orders. Of course, the true glory of this ability comes from the "strength bug." While I'm not going to argue whether or not it's a bug (it is), I don't think it deserves to be demonized as it has. Put simply, you can use strength-boosting equipment to equip itself if you're able to equip it initially. This means I can throw on a strength-boosting ring, equip this weapon, take of the ring, and I still have the weapon. What this really means is that you can invest up to 30 fewer hard points in strength and dexterity when determining requirements and maximum block rates. This means you don't just get 30 extra vitality, but effectively 90 (since you're not saving energy points since you shouldn't be putting any points into it in the first place, shame on you
). With 90 more vitality, a barbarian would get 360 more life, which becomes a few hundred more with battle orders. A Paladin gets a little less, but it still means a few hundred life (which isn't bad at all in PvM, and might make the difference every now and then in PvP).
+1 to Light Radius: This is worse than the conditional attack rating against undead. You don't need it.
Requirements -20%: If you're trying to get maximum block with a shield (using an axe), you're going to need enough dexterity for that and enough strength to equip the shield, this isn't making a huge difference, except for the fact that it makes the "strength bug" a little easier (since it takes less to equip the weapon, meaning you need fewer charms or whatever).
That basically summarizes (Ethereal) Breath of the Dying Berserker Axes. It gives you hit points, some decent leech, and a little more increased attack speed (which is usually provided by other items anyway). Let's examine Grief:
35% Chance To Cast Level 15 Venom On Striking: This is like the Poison Nova ability, except a little more relevant in 1v1 instances (bosses, PvP). It's still not very powerful though, adding 425-445 damage to your attacks for the next 196 seconds when it activates (more than enough time considering it activates on 35% of your hits).
+30-40% Increased Attack Speed (varies): This is less than BotD offers, but increased attack speed can be provided in a number of ways. 40% Enhanced Damage, 15% Increased Attack Speed Jewels are always fun, but aren't necessary.
Damage +340-400 (varies): This will give you more damage than BotD. Your maximum damage is irrelevant. Your average damage is what matters.
Ignore Target's Defense: This doesn't work on Champions, Uniques, Bosses, or Players. And it's worthless for Smiters, who automatically hit anyway. Still, it's a free ability.
-25% Target Defense: Again, this is halved against the important enemy types. It's not worthless, but it's not the saving grace of this item.
+(1.875 per character level) 1.875-185.625% Damage To Demons (Based on Character Level): It's conditional, but it applies to demons, at least. This means it works against ubers (for zeal paladins, or whatever; it doesn't work with Smite).
Adds 5-30 Fire Damage: ...This is the embarrassing mark that the Ral rune leaves on this weapon. Pretend it doesn't exist.
-20-25% To Enemy Poison Resistance (varies): This can be nice every now and then, but it's really not impressive given that your only source of poison damage is probably the Venom ability (with this adding 100 damage or so against enemies not immune to poison, against which this will only subtract 5% to 6.25% resistance because of the mechanics of immunity; this will break immunities occasionally, but not often, and never in Uber Tristram).
20% Deadly Strike: As if the 100 damage (before multiplications) that Grief adds compared to BotD wasn't enough, this boosts your damage even further. I've thrown numbers around for some builds (Zeal, Charge) and seen it add thousands of damage to the average damage (since you will not, on average, deal a Deadly Strike, when you actually deal one, those thousands of damage will actually be even higher).
Prevent Monster Heal: This brings us to the throw-away abilities of the runeword. This doesn't work on bosses or players, making it pretty ineffective.
+2 To Mana After Each Kill: Your mana should be fine in the later levels and mana per kill would be bad enough even if this were some number like 1,000 since it's worthless in 1v1 battles. The fact that it's 2 mana restored per kill just makes it embarrassing in higher levels. Some runes just suck... Ral, meet your friend, Tir. Go away.
+10-15 Life After Each Kill (varies): This is the runeword-generated friend of the crappy runes Ral and Tir.
While Grief has more "ugh, totally worthless" abilities, in my opinion, it outshines BotD in damage by such a long shot that BotD should just go home. I've seen the +400 factor add thousands of damage to fairly cookie-cutter, plain builds, and the deadly strike does similar wonders. With a Highlord's Wrath (admittedly not advised since Mara's is so nice when you have a 30% resistance one), this damage shoots up even more.
Personally, I like Grief, Fortitude, and Phoenix for massive damage (which is pretty nice for Smite, reaching over ten thousand). Charge can exceed twenty thousand; Zeal can be in the mid-teens of thousands (per hit). And with crushing blow added through other equipment, this would mean you would have dead ubers in a matter of seconds. Smite, for example, can hit 4.1 times per second. With 11-12k or so damage per hit, and with Crushing Blow on just about every hit, you can take down an uber easily in less than 10 seconds. And, yes, this leaves enough room for maximized resistances. The only issue your resistances would have is with Mephisto, against whom you would simply switch to Salvation (an amazing 1 point investment). You can easily afford to lose some damage by giving up fanaticism. He might take 10-15 seconds.
So, in short, BotD gives you a few hundred life. And, as it has been said so many times before, in so many different ways, you're much safer when your enemies are dead. And they die much quicker when faced with thousands of additional damage.