With so many shows officially released You need not depend upon audience recollections or in fact, anyone else’s opinion. You can hear for yourself and decide whether they are your cup of tea. Personally, I find them maddeningly inconsistent so I listen to the recordings I enjoy and don’t bother with the rest
While in the studio to record Terrapin Station, producer Keith Olsen cracked the whip and demanded they up their game. I don’t care for his production but their live shows in ’77 benefitted from his influence. This suggests they had the capacity to play at a consistently higher level but lacked the interest or drive to do so. This inevitably leads to a discussion of their so-called "ragged but right" ethos. I’ve already expressed my opinion of this in the past, so I won’t repeat it here.
As to the "sting", for me it's out of tune vocals and at times, Garcia's wayward intonation. My ears/brain have a low tolerance for out of tune music.

