My first recollection of GG was in 72 or 73, they were backing up Jethro Tull in Chicago, who we all were keen on seeing...I remember asking my friend who was in charge of acquiring the tickets, and the mind candy for the evening, who the back-up band was...needless to say, my reaction of "Gentle what?" was echoed by most of our group, about 10 of us.
All I remember of the show was... Gary Green wore these cool red gym shoes that were up to his knees (and that some of us later bought), Ray Shulman played this incredible long violin solo, Kerry Minnear played this incredible vibes solo, and... I personally enjoyed them better than Tull. That show turned me into the GG fanatic I am today.
I have seen them many times after, including all the garbage with puppets and dolls sticking their heads out of the curtains... but when they were playing music, GOOD music, no one was better. I remember the show where they all played guitars, including John Weathers, who made no attempt at hiding his flubs, and that was the last time I saw them...