Well, one guy wrote (or nicked?) more hit songs. And the other guy has, or had, a lot of Castles and a really hot, much-younger wife. Either way, they're both filthy rich.
Okay, so Ritchie is the (mostly official) father of Speed Metal. And, overall, he's a better soloist than Jimmy.
But Jimmy wrote some incredible arpeggios and complex rhythm structures. And - according to The Hammer Of The Gods - he dated at least one 13-14 year old girl.