Did some exploring of some outer areas today. Also found you can do some pretty cool shots with the drone camera.
Edit: I've been playing this solidly all afternoon
The way the combat can just break out of normal exploration is great, and there's always a reward for you taking part rather than just getting sick of it and driving on by. I've unlocked enough ram to make cars explode, which has been great fun with the gangs that hang around by them.
That and timing it so cars explode on the motorway as I'm wheelying past on my bike