A charging unit always strikes first, even with Great Weapons. Also remember that any troop killed may not strike back- so, if you get 5 kills, most likely that's none coming back at you- so I'd really recommend the Great Weapons. You will very likely get four or five kills with them, and then take nothing or very little in return.
I'm glad to see you are skilled in Mathhammer. There can never be enough people like you and I. I'm also very amazed that you went and caculated the numbers to try and find unit effectiveness- very few people actually do that, although it is one of the most effective ways of finding what's good and what isn't. So, sir, I salute you for bringing math and gaming together to your advantage. Hashut!

^^ very good post. I think I'll make a card telling you when to use which for my tactics article.
Id skip the math and think of purpose. I use the blunders for chewing through rank and file like orcs, and bull centaurs for enemy cav, so they need the great weapon can openers.
That is true. However, you have the option of either, so it pays to know what to use.
i always thought they always striked last even on charge too. ill have to check that up.
doing the maths is good against a certain opponent, but its never te best way of choosing effectivity for a battle, as if you equipped all your models with 2 hand weapons you would be upset when your only available target was a dragon or something else very tough. then again you would be better with 2 hand weapons against infantry.
If there's a 90% chance that you'll encounter infantry and a 10% chance you'll encounter a dragon, then that choice of hand weapons was more effective.
You can do the math against one opponent. But it's more accurate to calculate against a number of opponents and combine the results.
Bull Centaurs don't count as cav for the purposes of great weapons, so they still get +2S. They only count as cav for Unit Strength.
But they don't becauae in that section it says they only get the save if they consist of two creatures (eg man and horse)
The way I read it is that they are exactly like the Centigors. US2 but with all the other rules that infantry have (Parry bonus, +2S Great Weapons).
I'll add to this a further level of complexity. This varies for each unit. I'd say that it is for orcs for example it is better to have an additional attack rather then a higher strength hit. Of course this is all dependent on what you are attacking. So in short the math approach is a good one it doesn't tell the whole picture. YMMV.
No, there is a very clear answer.
Even if they only get a +1S, the great weapons are still better against heavy armored opponets and high toughness opponets. They are also better against cavalry since you need the hard-hitting power, plus you are likely to go last during the first turn anyway and cavalry vs. cavalry battles tend not to last much longer than that.
Additional Hand Weapons are better against hordes of light armored enemies.
So it all depends on how you intend to use your bull cavalry. If you want them to be can-openers, then use the great weapons. If you intend to use them to flank and smash large blocks of enemies (particularly those with good leadership) then go with the hand weapons.
Though between the two choices, it seems far more likely that you are going to be using them for the former. You have other things available to deal with the hordes (and if you can flank them and charge, 80+% of the horde blocks will break when you slash them up with the great weapons.)[/align]
The problem, I guess, is that in a tournament setting (or in an all-comers list) one either has to take GW
OR extra hand weapon.
I would think that CD Warriors and even Hobgobs could stand a decent chance against the kind of stock standard infantry you're likely to encounter in a horde army.
With extra hand weapon, BCs
can kill lots of stock standard infantry, but is that really what BCs are for?
I would argue that in an army which lacks heavy cav, chariots and uber heroes like Vamps or Chaos Lords, Bull Centaurs are the unit which should be performing the can-opener role. In other words, give them Great Weapons so that they can perform the role to which they are most suited to the best of their ability.
Let the CD warriors, Orcs and Hobgobs deal with the normal infantry, there is no point in letting BCs get distracted by the small stuff.
Just my 5 cents, take it for what it's worth

We couldnt find a clear answer to that over at HoH either.
That's hardly surprising, since there is no clear answer.
They're taking an army list that should have been updated years ago and trying to interpret it through the lens of 7th edition rules.
There is no answer, just heated debate about a question that only GW can give a definitive response to.
Sorry, I know that wasn't very constructive......
It's a nice sentiment, but it won't help.
Other have tried and gotten nowhere.
GW will sort it out when they're good and ready and not a second before.
GW has ever had a curious relationship with their customers.... "love/hate" comes to mind...
It was never that great to begin with. I'll stick with it being a support unit only, rather than one that races out to kill the enemy from the first turn.
The only official mention of CD in GW is the raveneing hordes army list.
direwolf is not official nor has it ever been...
quoting direwolf is like quoting roolz boyz... 50% either way...
but in most cases likely to get your argument thrown out...
that this "interpretation" is based on '04 chronicles...
which was for an enirely different editon of the game does not bode well...