The Boston Music Hall was the site of my first show, but it wasn't until 6/11/76. I loved that room and saw a few more there after that.
My favorite era was probably 68-79 or so. Up through then, you could count on hearing new tunes, often very different from the previous material, on every tour. When Terrapin and Estimated Prophet came out, it blew everyone away. Plus, the format of the shows were less predictable. By the 80s, it had ossified considerably. But, I've got to give a shoutout to the 80s for some very interesting sound quality changes, notably the Modulus instruments, and some good songs here and there, like Brother Esau and Throwing Stones. But, I agree with some of the criticisms regarding the change in the audience as the 80s rolled on.
On a related note, so many of my heroes of the 70s became junkies in the 80s. Jerry, Jaco, Gil Scott-Heron. It was hard to watch.