Raise Your Antennae High!
In my opinion, quilt guilds are ALL about the programs and the people. One without the other is not good. Yes, you definitely want to visit, perhaps a couple times, to get a "feel" for the group. Are you approached and welcomed by the members? Do they encourage you to join? During break time do they comp up and engage you in conversation? Are they just plain friendly?
And then what do they do, and what do they offer? Do they schedule a variety of speakers, and have a season's worth of quilters printed so you know who and what to expect? Are the speakers varied (traditional quilting, modern quilting, different techniques, perhaps color theory, etc.)? Do the speakers offer classes?
Does the guild make charity quilts? Quilts of Valor? Quilts for babies and seniors in nursing homes?
Does the guild schedule Sit & Stitch sessions and retreats that are affordable? (And by the way, are the classes affordable?)
I hope I've given you some ideas of things to look for when considering a quilting guild. The guild I'm in now is absolutely WONDERFUL . . . however, I had to go through three bad ones to get there! Good luck!