Ok lets break it down then.
Assuming The Following:
LV14 Crusader Vs: Barbarian6-9/FrenziedBerserker5-8
Reason for Lv14? I was going to choose level 12 as the encounter point, but realized that I would be shoehorning the Barbarian too much by forcing it to choose a race that grants a bonusfeat at 1st level, because a lv12 character cannot possibly attain Deathless Frenzy without multiclassing into Fighter for the bonus feats(which the Frenzied Berserker STILL has the option of doing at lv14). How does the D2Crusader benefit from this? He doesn't have to waste a feat at level 12 to attain Aura of Chaos, instead getting it at level 14 as a 4th martial stance. So both sides benefit from a little more flexibility. I am FULLY aware that there are other methods of attaining the tools(I.E. class features such as Rage, and Martial Stance(Aura of Chaos)) and have purposefully left these out of my analysis in an attempt to keep things from getting too out of hand. For the Frenzied Berserker, Barbarian and Fighter levels will be accepted to help qualify for the FB Prestige Class, and the D2Crusader will be stuck singleclassing it.
As a handicap, I'll allow the Frenzied Berserker to take levels in fighter in order to qualify
Now lets analyze these Two PC's according to a few different categories.
=============
Feats
=============
The Barbarian(Or Barbarian/Fighter) needs four feats to net himself entry into Frenzied Berserker. (Power Attack, Cleave, Destructive Rage, Intimidating Rage) Leaving him with very little room for customization in this area. In order for a single Classed Barbarian to qualify for this feat at level 6 he'll need access to an extra feat somehow(Human or Strongheart Halfling?) or access to Flaws. Assuming either of these races, the Frenzied Berserker will have 2 Open feats left, which depending on the level of encounter optimization he will need for this match will either be chosen in order to assure a draw (such as the aforementioned Pain Mastery from Savage Species, which requires toughness, AKA "the best feat EVER"), or guaranteeing that he cannot be hit once, giving him a chance to possibly win.(Not sure what 2 feat combo could pull this off really.) ALTERNATIVELY, it IS possible to qualify for this class with a single level of Barbarian, leaving you to take a few levels of Fighter, for the two levels of fighter you could take to free up some feat slots. (Power Attack and Cleave are both Fighter Bonus Feats)
For the Crusader, things are a little more flexible. The only feat you need to pull off this particular build is a little doozy called IMBUED HEALING. With no PrC to qualify for, the rest of your feats are free for whatever you want, about 4-5 feats remaining(based on racial choice). Depending on the level of optimization, you might go the Dodge/Mobility/Elusive Target Route to negate the massive Powerattack damage that the Frenzied Berserker has. There's quite alot you can do with that many feats. The SKY is the limit!
=====================
Class Features
=====================
The Barbarian's Class features are pretty straight forward, Rage being the staple of this build. Also, the conventional wisdom around these parts is to replace fast movement with Pounce via Spirit Totem alternate class feature. The only other part of Barbarian that could possibly come into play would be Uncanny Dodge(In case he loses Initiative or is otherwise caught flat-footed). Damage reduction and Trap Sense will not come into play in this scenario. And...OH and hey! Hes also Illiterate! As far as Frenzied Berserker is concerned, Deathless Frenzy is another staple of this build. The Basic FB strategy will be to take full advantage of Powerattacking on a charge for a tastey 3x(or more) bonus damage. Depending on the build, Greater Frenzy is attainable by 14th level. The decision to take levels in fighter will make it possible to attain Greater Frenzy, which brings the total strength bonus to +14 when raging AND frenzying. Pretty scary stuff!
The Crusader has alot going for it. Firstly, Steely Resolve helps him absorb a bit of extra damage without dropping, Giving him an effective 20 extra HP for the purposes of this encounter, and DieHard gives him an extra 9. For the Frenzied Berserker, HP is largely irrelevant in this matchup, but this is not the same with the crusader. Furious Counterstrike means that supposing the Crusader somehow loses the Initiative and lives through the onslaught, he will have a greater chance to hit with his counterattack.(Elusive Target goes a LONG way towards ensuring survival of a Full attack from the Frenzied Berserker). His Martial Stance(Aura of Chaos) is one third of what makes him the D2Crusader, so we will assume he at least stays in this stance until he makes a hit. MANEUVERS are the real advantages here. Moment of Alacrity virtually ensures that the D2Crusader will win Initiative. EMERALD RAZOR almost guarantees that the D2Crusader will be able to hit with at least one attack. IronBones(DR10/Adamantine for 1 round after a successful attack) could help keep you alive assuming the Barbarian doenst have an adamantine weapon already handy. Disrupting Blow, depending on how high your strength modifier is, could cause the FB to lose his turn!(If he doesnt have some way to cover his weak Will save, like Steadfast Determination. Shield Counter can go a long way towards keeping you alive for a round.
================
Equipment
================
This is where things get crazy. Anyone with the appropriate wealth of a 14th level character could easily pump their AC to insane levels, or do any number of interesting tricks. Since neither has more wealth than the other, then neither has the advantage in this area.
More later...