From just a tonal point of view, regarding the Dead'd 90's sound, I didn't like it too much. Jerry's guitar was thin, the "acoustic" sound of it to me always sounded very over-processed and not really like an acoustic at all, and his overdrive of the period I thought was harsh sounding. Vocally, obviously the man was not in peak form - there times I wished they would just play all Bobby and Phil tunes it was so hard to hear.
Vinnie's keyboards - yeah, the "Radio Shack shit" posted earlier sums it up pretty well for me. Whatever he was using didn't sound, I guess organic is as good of a term to use as any - it always sounded like a bad keyboard patch of a piano, or organ, or whatever. It often reminded me of a freaking merry-go-round, honestly.
Weir's guitar tone was extremely aggressive in the 90's, but I realize that he had to be more upfront as Garcia declined more and more, so he gets a pass on that from me.
I had pretty much given up on them by '92 or so - only going to local shows to see friends, hang out , and carry the torch, but not expecting much from the band themselves by then.
Out of the loop? I didn't know there was a loop!