Was not too good for me. Latency was all over the place. Couldn't join Crusader's game but he could join mine. WTF is up with that?
Taken from forum thread, seems to be a workaround to be able to join group games etc.
"Me and my girl have been testing around on this for a while and we figure it's some kind of party locking issue that basically banishes people to limbo.
That said here's a little thing that worked for us to allow us to play together and use party chat. If it can be extended to work for larger parties seems likely but I didn't get to test that yet.
Here's what we did:
1. Player A create game, player B wait in menu's
2. Player A send invite to B(do not use quickjoin) , player B accept but wait in menu
Player B Do not click resume (just don't)
3. Wait a few minutes... I haven't timed it yet (waiting for afk seems to work)
5. Click resume
B should end up in the party with A.
Had a chance to test this 3 or 4 times now... you really need to do that wait it seems.
Maybe it'll work for you in some way or the other this way... worked for us so far."
Couple people have confirmed that for whatever reason the above works.