Rooftop rumble is faster IMO
It's a fairly standard payout about 12-13k but the RP is good. About 2500-nearly 3000 and much quicker to do than Coveted.
I'd do rooftop rumble but I've only just got this character to level 51, Though I was at level 40 the other day, and mixed up with coke sure helped speed that up.
Buzzard ia for pussies sure, but it makes like work when you want to level up faster than a snails pace. Good for lower levelers too.
Buzzards are pretty easy to take down if you know how to. Tanks are for f*ckin pussies.