I would go (rather erractically) to one that I no longer have access to due to distance.

As for what it is like...
It can be very good. I found meetings to generally be helpful, just for that IRL connection with other BPs that we often lack. Or for finding out about local events relevant to mental health or local political issues if that is of interest to you. (For instance, there was some legislature that was to move the state mental hospital from the where people actually are to basically the middle of nowhere. People tended to have an opinion about that(!))
There are rules -- good ones. Like speaking from "I" statements. In other words, to NOT getting all preachy like, "YOU should do this, YOU should do that" (Which we all have experienced and it's not only unhelpful, it sucks!) Not yapping with someone else or interrupting while someone is sharing. Those kinds of things.
You can share or pass. No pressure.

One random factor that can really affect one's experience is that anyone can show up. Soooo, sometimes someone might be there that you don't really like. Hey, I'll admit it, sometimes I'd think (just to myself of course!!!), "oh crap, so and so's here". Not nice, but there you have it. Though all are supposed to be agreeable to the rules, sometimes someone's not, and if the facilitator doesn't speak up, that can be not great.

The thing about the randomness of the mix of participants also means that one should not write off going based on going a time or two. Maybe those were just not great weeks. Maybe don't go for awhile and then and try again. There tend to be some people who show up a lot over a long time, people who attend pretty regularly for a short while, erratically over a long while, a couple times, once, you get the picture. So it's constantly evolving.

As for apprehension over the first time one attends? Virtually everyone experienced the same thing, so no worries, there's plenty of empathy on that!