Once you learn how to play the game, it is quite fun...
The shooting is much much improved... the aiming is nice, but I usually do a lock-on aim and then aim a lil on my own for a headshot, save ammo. The ability to hide and to blind shoot and shoot around corners is awsome.
The driving is much better than the rest of the games once you get used to it to. I don't know what you all are talking about with speed, it seems like I'm doing close to 200mph on the bike when topping it out, and if you hit something the wreck is realistic and you will die at the speed. Also it is funny to be in a car going fast and t-bone a car or hit something solid and fly out the windshield. You have 3 different brakes, learn how to use them and driving is easy.
Though they left way too much out, I want all the stuff from San Andreas. Especially the fighter jets, you can't fly any planes in this one. The gangwars, and ability to raise certain abilities I miss as well.
I am about 65% done and on the last story mission. Will have to play again to see how my choices make a differnces, I have a feeling at the end you make a huge choice to change the ending.