I'll be honest: I like San Andreas a HELL of a lot more than I do GTA IV. There are still some things the Saints Row series does better (ability to shoot out of cars with more than a SMG, 360 aiming while in a car, cruise control, gang warfare is better), San Andreas is STILL worth playing. Just don't do any of the gang wars during the first Los Santos chapter. You don't get to keep any progress in it when you're exiled.

Do you like first-person shooters, but hate all the modern "improvements" that the era of Call of Battlefield: Medal of Halo Forever has brought us, such as regenerating health, the "ability" to only hold onto two weapons at a time, and bland generic enemies? Do you want to face an insane amount of enemies with an equally insane amount of weapons, including a FUCKING CANNON? Were you disappointed by Duke Nukem Forever in any way? Then this is the game for you.
The only modernizations that Serious Sam 3 went through were the additions of sprinting, melee attacks not involving a weapon, looking down iron sights of specific weapons (pistol and assault rifle), and reloading specific weapons (pistol, regular shotgun, assault rifle, and the Devastator), and these changes feel kind of... welcome, as they aren't abused. Other than that, it's a Serious Sam game. And it is fucking glorious.

The most "cartoony" of the Serious Sam games, it's still as unrelentless as the other games in the series. In fact, it's the game that got me into the series to begin with. Pure, unadulterated fun.

Also, in what other game can you go up against five giant spiders (we're talking BUILDING-SIZE here) at ONCE and still win? :D