The Roots and Mos Def are so unheard of these days by the kids that think that they know hip hop. The two groups you mentioned are what hip hop is all about. I used to love them back in the 90's. The crap they play today though is what most people consider "good hip hop" and it's sickening. I wish Tribe Called Quest never broke up. Oh yeah there is still De La Soul too , so I guess there are a few rare gems here and there.