portishead overrated???

i have been peeking into this site for a couple of months now, but one thing that has kinda floored me is how much you guys like portishead. don't get me wrong, portishead is a solid group that occassionally slaps together a nice track, but i've never considered them an outstanding group. actually, i haven't been too impressed with massive attack's more recent work and thats another group you guys seem to be big on. what makes these groups so good? to me they are just the most popular groups, but any media person will tell you that popularity doesn't equate to talent.

to give you some perspective, i'm into shadow, dining rooms, pelican city, nightmares on wax (specifically smoker's delight), some krush, some cam, thievery corp, and just got bonobo (thanks to some suggestions in one of the boards).