Picked up MP3 for ~$5 over the Autumn Steam sale. I think it is a fantastic game. Very fun and very good graphics. Also the animation is top notch. Very natural and smooth.
My only complaint is regarding the enemy health. This game commits the ultimate shooter sin: bullet sponge enemies. The Uncharted games have the same problem.
The unarmored baddies are fine, but the ones with body armor are ridiculous. Even the basic guys with Kevlar vests can take 7 or 8 rifle rounds to the chest before going down for good. And don't get me started on the big guys with helmets. They can take 18-19 rifle rounds to the face before dying. This is on medium difficulty.
For reference, my dad and I went out to the farm about a month ago to shoot his new Ruger American 308. We stacked two 30lb 8x8" steel plates together and shot them from 200 yards, with low pressure target rounds. It went cleanly through both of them like a lightsaber through butter and just kept on going like they weren't even there...
BTW the American 308 is a fantastic rifle. Even has a free floating barrel. Walmart carries it for dirt cheap.