We do, it's most of what we do. We have only recently started looking for couples instead of singles. Everything that we used to do was with single guys and girls. Mostly single guys because they are so much easier to talk into threesomes than single girls.
We would never even consider meeting a guy through the swinger circles though. We only do it with friends. I'm sure that there are some good single guys out there, but it's so hard to tell them apart from the cheaters and fakers that it isn't really worth it when there are so many willing single guys that we already know as friends.