they're OK... you've a 'target lock' button as well as a fire button... plus you can crouch (better accuracy, plus you can duck behind things, or roll sideways if someone's got you pinned.)
One problem with ducking behind cars... they can be taken out with ONE bullet - just aim for the gas cap.
What's got me hooked is the gameplay depth. Wander into a bar, play a game of pool (and walk out with the cue still in your hand... good for beating the crap out of rival gangs without attracting One-Time...) Jack a lowrider, get the friendly neighborhood mech to work on it, and go have a hoppin' contest. Wanna show off for your homeboys? Bring back a sportbike and do 'donut' burnouts in the street... Low on cash? Jack a taxi, run fares around town. Or, find a pimp's car and take HIS job for awhile, ferrying hookers and beating up the johns who won't pay.
Etc etc etc.
But the "Sanchez" motard is by far the most fun. It's not insanely fast, but it corners really quick, even on sand.