I can't remember the exact critical calculation, you can find it on the forums somewhere, but it's worth pointing out that you can get a critical and still be in the normal range of damage if you didn't cause a critical.
Critical hits deal double damage if there are no other critical damage bonuses involved, so the only way that a single-figure unit can have a critical hit which still falls into the standard damage range is if that unit rolls its bare minimum damage and has only the base critical damage multiplier. The Serrated Longsword shown above increases the multiplier to 3.5 (it adds 1.5 to the base multiplier of 2), so the bare minimum that you could manage with that weapon on a critical hit is 1.75 times your normal maximum damage.
The specific conversation you're speaking of is more likely to have been dealing with critical hits made by multi-figure units, in which case it's relatively easy to fall inside the normal damage range, as if X is the per-figure maximum damage and the unit contains N figures, the standard damage range goes from 0.5*X to N*X, while the critical damage range goes from X to 2*N*X.
As for which one I'd use? Probably the sword, because most of my champions that actually get involved in fights are spellcasters, so the critical damage chance and the critical damage bonus, both of which affect damage spells, are appealing, as is the initiative bonus. Curgen's Hammer might be good for a late-game Warrior supported by an army, though.
And yes, I know I'm a bit late to the party for replying to that particular run of posts.
@Above:
Is he threatening to kill himself if he doesn't join with himself? That man needs counseling.
