Gza is an institution of great lyrcism while Rza is hit or miss a lot of times. Rza was ill back around 98 but he hasnt been that good since. he's been erratic on the mic while Gza has been old faithful. Rza when he has it going is better than Gza in all MCing attributes, but Gza is just more consistantly brilliant than Rza. Gza, along with raekwon, method man, and u-god are even better on their solo albums. out of all the weak albums of the 2002-present era Gza had the best album cuz he came through so well lyrically and made up for bad beats. if Rza was more consistant i would give it to him cuz he is a better all around MC than Gza.
assuming we're talking about who is the better MC Rza's beatmaking ability is irrelivent in this comparison.
Gza gets my vote.