Online was just a constant grindfest of heists that got stale quickly due to restrictive mission design (oh, you stepped on THAT curb? Mission fail, restart) and cheaters.

Some cheaters were cool (several people gave me top-end cars via various dupe glitches), some attached things like steel safes to your character so you couldn't shoot or do anything else.

I never bothered to finish the story mission. I got right up to the last mission and stopped there.