Playing on PS3...
So bout 2 hours ago I was pretty annoyed, I lost my character and my money, had to start over and couldn't even get past the dreaded Lamar race I've attempted dozens of times and completed 4 or 5 times due to losing my character.
And then it just started working. Did the tutorial, got into a game with my buddy with out even trying (after Lamar race it just put me in a game with him), got the hold up mission, which he came along for. Then I got the Simeon mission to get my car, after that it was just great. Every Job and Mission we tried together loaded properly. It was difficult filling up a game, we found if the host uses the option to "Invite from Skilled Players" instead of Auto and/or Friends/Crew we had better luck. Even in my giant public crew it was hard getting people from there to join. We ended up doing a dirt bike race, boat race, a couple GTA Races, a couple DMs, and then a mode where two teams try and steal some drugs and bring it to a safe house. Everything just worked, it was great, I hope it keeps going. A few things that may help people...
1) When you send an invite out for a Job/Mission, people who either don't see it or don't accept/reject it for whatever reason, their invite never goes away. This means if you send an invite to 14 people, if all 14 people don't respond to the invite (they pop up as a text message I on bottom left of screen, hold D-pad UP and then X to accept), have fun with your 2 player match. The only invites which "refresh" and go out to a new/different player is when an invitation is either rejected or blocked. Otherwise it just hangs and you're boned out of an invitation.
2) I may be mistaken but I'm almost positive if you have Free Aim selected in settings, you will be matched up for sessions with other Free Aimers. I tried to join a friend with Assisted Aim and before I joined it asked me if I wanted to switch modes, I said yes and then everthing including Free Roam was with assisted aim. Afterwards I went to play with a FA friend and it asked me again to switch targeting modes.
3) If you play Job/Mission with people you like, but decide to go back to free roam, don't quit while in map vote mode, select Free Roam on the bottom right instead. You'll go back to FR with anyone else who selected that option. You'll remain in the same session as the people who continued doing Jobs, but you won't see them until they return back to Free Roam. If you had quit instead (O/X while in map vote), you'd go back to some other random session.
4) When you get your car during the tutorial, hold down Select and scroll to Enter-Vehicle (might be off) then select whatever option you prefer. Everyone is default for some dumb reason.
5) Haven't figured out how to mute specific people but you can mute everyone, or just allow Crew/Friends if you hold Select and scroll to Mute, 2nd to last option.
6) If you rob stores with some help, you can divvy up the money pretty easily, once again, hold down Select, Inventory, Cash... and I forgot the rest but that should get you close enough to figure it out.
7) When its time to get your first car in the tutorial, don't bother trying to get a super car from Vinewood, it won't work. No "premium" cars aloud.