I have plenty of Dead boots... and while most of the gigs have their great moments they're usually filled with boring jam sessions (for me anyway). Nothing against Dead though, I respect them a lot. They got their massive live success without any support from the mainstream media (in that sense they were a lot like Rush and DMB). And I love all the songs by Brett Mydland. Very beautiful.
They have always been virtually unknown in Europe, so I can't probably fully understand their attraction among the masses. They were so "American"... if you know what I mean... I guess they were sort of "hippie gathering"... and Phish adopted a lot of their old audience later.