I finally obtained Dragon Magazine #343 and got to see the Tome Dragon's stat block.
So let's have them duke it out in the form of a forum poll.
At a glance
Steel (forgotten realms, dragons of faerun)
Stats: 4HD/2LA, Small
Alignment: LN or LG
Adjustments: +2 con/cha
Natural AC: +3
Speed: land 60ft, fly 150ft (average), swim 30ft
Breath: line of acid, 1d6 & cone of poison, 1 con damage then 1 min later again.
Qualities: alternate form, immunity to acid, SR 16, spells; sorcerer 1st + cleric + knowledge & trickery
Spellcasting: Wrymling
VS
Tome (dragon magazine #343)
Stats: 3HD/5LA, Tiny
Alignment: usually lawful neutral
Adjustments: -4 str, -2 con, +4 wis/cha, +6 int.
Natural AC: +1 & +1 insight
Speed: land 20ft, fly 90ft (good).
Breath: Shot with a 5ft blast radius of sonic, piercing, bludgeoning, or fire, 1d8.
Qualities: Physical Frailty, Arcane Sight, Precognition, Telepathy 100ft, SR 11, spells; sorcerer 3rd + knowledge & auto knows all divination/conjuration
Spellcasting: Wrymling
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Extended Details on their statblocks
Starting ECL goes to the Steel with it's availability from level 5 on with LA buyoff.
By ECL 8 they both have 3rd level spellcasting.
Steel can learn any cleric spell, the Tome knows all divination & conjuration spells without using known slots.
By ECL 9 the Steel can pay off the rest of it's LA, for 55% of the game the Steel knows a higher spell level than the Tome.
Steel dragons can have 20 while the Tome is limited to 16 allowing the Steel to obtain more powerful class traits.
Both can take Loredrake, both lose their domain access by doing so, the Steel loses cleric spells but the Tome still knows divine/conjor spells.
Steel has faster speed, can swim, poison breath and can hit more enemies with it's normal breath weapon.
Tome has bigger bonuses to mental scores, Steel don't have penalties to con.
The Tome's maneuverability is better but it's natural weapons & reach are reduced by one size.
Steel has one point of AC more but the Tome sports +1 insight to AC (does not stack with foresight and such) which is applied to Touch Attacks.
Tome has a 3/day Alternate Form and the Steel has 5/day Alternate Form.
Tome comes with Telepathy without having to dip into Mindbender, Steel can access Telepathy before the Tome is playable.
Steel's SR is effectively 26 at ECL 5 (up to 8) if the opposing caster were the same ECL, Tome's is only 11.
Steel is immune to acid which when coupled with Mantel of the Fiery Soul & Troll-Blooded means immunity to lethal damage.
Steel's Moderate Arcane Shield & the Tome's Precognition abilities are not defined.
Likely Precognition is the source of the insight bonus to AC (scales up to +4).
Minor Arcane Shield gives a +10 bonus to the Steel's SR against 4th level spells, likely moderate upped the level of spell the bonus can apply to.
Aging
Tome's Free Metamagic doesn't give free feats, instead metamagic feats with less cost than X do not alter the action spent to cast it.
Steel's casting time remain changed allowing it to use a Spell Surge + Invisible Spell for casting two spells each round.
Steel gets enthall, Charm/Suggestion and their Mass versions.
Tome gets Clairaudience/Clairvoyance, Planesshift, True Seeing, & Astral Projection.
Steel's DR caps at DR 20/magic, Tome's is DR 15/magic.
Both have the same AC & Flat-Footed ACs, Tome's touch AC is two higher (thanks to the insight bonus).
Other
Steel is official material.
Tome knows all sorcerer conjuration spells (it bears repeating, else it's a no contest and Steel wins).
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So which one do you like better and should win the poll?