It's a shot in the dark. I went on one elk hunt with a guy I'd talked with a lot, but never met before the hunt. We didn't kill anything (short version, weather bit us in the butt) but we had a good hunt and got along great. Went on one with a group I didn't know and it wasn't awful, but there was some conflict. A couple of them I'd hunt with again, but not the whole group, even though the success rate was 50%. Then another hunt (moose hunt) with one of my best friends, a couple of guys I knew but that that well (we were all in one cabin), and three other guys I'd never met or even talked to before we started planning the hunt (had to have a minimum number of hunters to go). One of the best hunts I've ever been on. No moose were killed (again, weather--but we did get to hunt), but we had a blast.
Big thing with me is cooperation. Someone with a "lone wolf, my way or the highway" attitude can really spoil it for the rest, as can a freeloader who wants to sit around and watch everyone else do the cooking, get the water, set up camp, gather wood, etc.
Research it as much as you can. Get to know folks as best you can. Be sure as the new guy in the group you pull your weight and then some. Even then, you are taking a chance. If you have limitations that could hinder the group (out of shape, short-winded, bad back, etc.) be sure the rest know this in detail ahead of time and be sure everyone is ok with it. If you have limitations and are still welcome, go out of your way to make up for it if you can.
For me, a really bad experience can be worse than not going at all.