Thanks all advices. Previously, I always read the article for individual comera info and performance. Yesterday, I have found an article comparing Rolleiflex, Hassy and Mamiya 7. It is interesting. If you have time, please read the link. This is only comparing specific cameras performance.
But I believe, the Rollei deliver pics with European feel and Mamiya deliver different taste/feels and depend which you like. But it is difficult for me to really taste two cameras' printed pics.
http://www.hevanet.com/cperez//test/fourcameras.html