I agree with Bill to a large degree if what he's talking about is what's being done with the music today by the cover bands
There's a huge difference between cover/tribute bands and musicians taking the feeling of the tune and reinterpreting as they hear it or how it makes them feel emotionally.
THIS is the passing along of the musical/cultural tradition that one poster mentioned - purely restating what's already been said is certainly good, especially for people new to it who never saw the Grateful Dead live, but if you were a member of that band, how really interesting could it be to play the music as a tribute/cover band? To that extent, get Bill's comments completely. Warren easily evokes the spirit while being his own. Kimock's almost incessantly brooding style doesn't really evoke any spirit - at least not to me.
This is also what deals with what one poster said about comparing it to Duke Ellington. Again, musicians adding something of themselves as they pass the 'tradition' along, not simply performing a story retelling.
I was at the Rex Foundation Benefit at the Fillmore earlier this month and I'll tell you what, David Nelson's band was more of a reflection of the 'thing' than i've heard in a long time. It naturally added his and his band's particular voice to the music while completely within the spirit of it.
If i was looking to point someone new to something that represents the spirit, I would point them to David Nelson well before I would take them to a Furthur show.