ive heard thats how petrucci plays so good on the albums but when he plays live he messes up the solos, like As I Am at Budokhan!
when hes doing the chromatic fast alternate picking section in the solo he hits a couple of duff notes, but he plays a 3 hour set almost perfectly, i wasn't really criticising him lol
He usually messes up the arpeggios in the beginning of The Glass Prison.
No rhythm guitarist I'd say, I can't hear Pinnella well enough as it is.