LOL, It isn't necessarily their 'flow' that regards them as a good MC, but their lyrical content, story telling ability, vocabulary, poetic influence that makes them good. I'm going to go ahead and agree with you that U-God isn't as good, however, have you heard his album U-God - Golden Arms Redemption from 99? GZA & Inspectah Deck are my favorite Wu-swordsmen. Some of the best Wu-Tang releases aren't even core members. I suggest you take a very close look into Wu-Affiliates(Wu-Fam)... Killarmy, Shyhiem, GP Wu etc.