Death match can be frustrating if there are too many people, and boring if not enough--- I like about 6-7 in a death match-- with a medium/long distance respawn (depending on the area you are playing)-- and of course with nobody quitting-- about 15 minutes seems to be a good amount of time-- any shorter and you can't get in a groove, longer and people get bored or frustrated and quit.
I was in a good GTA race group the other day-- we had 7-10 people with fairly few quitters... were doing "random" races, 2 laps, in supercars with all weapons..... seemed to be a good combo... played about 90 minutes before people started dropping out.
The only time I ever quit was in a sesssion of death match where we started off with a good amount of people but the person set it for a ending of $10000 (first one to $10000)... everyone dropped out except for me and another guy-- I quit with about $4000 and he had about $5500-- we had been going at if for about 90 minutes in the one game and I finally started catching up somewhat (figured out attack he wasn't good at defending) but it was about 3:30 am and I figured the game wouldn't be over for another 90 minutes to 2 hours.