This was my primary fantasy for a long time, until I fulfilled it.
Here's my advice. If you want it to happen, don't plan it, and if you do plan it, make sure it's you and not Michelle planning it. It's a hell of a lot of work, and the outcome (at least in my case) wasn't nearly all the effort.
In my case I planned the entire thing myself, finding the location (didn't want to do it at my house) and the guys, etc. The first time I tried to put one together it totally flopped (only 1 guy showed up). The second time around, it came out ok. 5 guys showed up. The thing that I found hard was that to me I felt like I had to try to please all of these guys, and that alone took away a lot of my pleasure.
So the conclusion that I came to was that I would never plan another one. If the opportunity arose to do several guys at once, I would probably take it but I wouldn't go out of my way for it. It has and I have, and in those cases I have tended to enjoy it much more. I think because it wasn't really expected by anyone everyone had less expectations and was happy with whatever happened.