The scarab grants Jaime a number of powers. It provides him with a form of mystical sight, providing him with information in an unknown written language which operates whether the scarab is active or dormant. It is also capable of communicating with Jaime in a more comprehensible fashion, informing him of what it can - or needs to - do in a given situation.
The suit has been seen to produce a seemingly electricity based energy cannon, and a set of dual-purpose wings/shields enabling Jamie to protect himself from energy blasts and to fly. It's also able to protect him against atmospheric re-entry (although how is unclear), as well as providing him with strength beyond that which he might normally possess, such that he can break someone's wrist by squeezing it with one hand. The scarab's 'pinchers' spark when activating one of the suit's powers, or when de-activating the suit.
It seems to be nearly as powerful as a Green Lantern's ring, an impressive feat for such a little known mystical item.
Ehh. He was on the defensive for most of the fight. Plus Guy wasnt thinking straight. He seemed pretty beat when Guy gave up, after seeing that he was crying and was a kid.
Yeah I think there just isnt enough that we know about BB's powers yet. He was on the defensive against Guy cause he didnt know WTF was going on. But he withstood all Guy could dish out.