Laughing at the jaded haters in here. They're right, it's not classic Splinter Cell. It's a completely different type of game, and if you walk into it acknowledging that, you'll have a good time.
Play it on the hardest difficulty so that playing stealthily is a necessity. Play it on the easier difficulties if you want it to be more of an action game.
The coop is great. As is the single player. The environment plays a big role in setting up traps. The AI seemed pretty solid from what I could remember too; calling in reinforcements, searching an environment for you, and generally being more threatening than guards in, say, a MGS game. The story falls apart towards the end though, unfortunately.
Definitely give it a spin. It can be had for next to nothing these days. It's very much worth it if you're open-minded and don't give a shit about what Splinter Cell once was.
Loved the time period and look and feel of the cities. 
