This is the specific item/feat combination that concerns me slightly:
Strongarm Bracers (MIC, use weapons 1 size larger), power attack, improved bull rush, knockback, combat reflexes (from spell heroism), spiked chain.
All this gives him a 20' reach with +14/+9 atk, 3d6+10 dmg and 3 AoO per round. If he uses power attack -2 atk / +4 dmg, that gives him +12/+7 atk, 3d6+14 dmg, +19 bull rush modifier (+7 STR, +4 size, +4 improved bull rush, +4 power attack).
With this combination chances are that any melee enemy that tries to approach him will not only get hit and suffer considerable dmg, but also get pushed back and have to make the approach again if they want to fight in melee. Even other large sized creatures have extreme difficulty countering that bull rush modifier.
Now to clarify, I'm not asking on tips on how to deal with this character. I have plenty of good ideas on that subject. Grease on the weapon, will save requiring debuffs on the minotaur, ranged combatants, wide open areas with room for the monsters to manoeuvre, high tumble or high AC monsters, etc, etc, etc...
What I am asking is this: According to the opinion of other experienced 3.5e players and DMs here, does the above character feel balanced for his level? I'm a bit torn on the subject myself. So far he doesn't feel overpowered and I'm more concerned with how he dominates tight spaces making it difficult for other PCs to shine (it's a 6 PC party). That is easily fixable however by providing more open spaces and tactical situations in future adventures. I'm just trying to err on the side of caution here by asking what others feel about this as well.
edit: Character Sheet