yes, petrucci definitely technically satriani'r cheye better. his compositions are also outstanding. all the songs in "suspended animation" are really mind blowing. but satch is satch man.
also, i've had the feeling that when shredding petrucci is not that melodic. he is definitely a more melodic shredder than batio or jow stump, but not as melodious in shredding as the yngwie of old times, and, more notably, shawn lane.