Patience doesn't necessarily have to be a virtue.
I love the point system to upgrade weapons and gadgets; however, it becomes tedious after a while because I found myself restarting checkpoints to complete the tasks because it's the easiest way to get points. Otherwise, I love being able to earn customization rather than instantly having the option.
The gameplay is well done as the controls are placed well for the controller, and the AI is decently intellgent. Although I'm playing this game on "Rookie" or whatever the easy setting is (I play campaigns mainly for the plot line, not because I'm an expert gamer), the game is still surprisingly difficult at times (probably because I either haven't shot out a light, or because I shot a light that was too close to an enemy and my cover was blown).
The graphics are especially appealing. If I didn't have a controller in my hand, I would have thought it was real instead of animation. Everything looks so realistic and pretty (even the Iraq mission), that I am blown away.
If you're looking for something other than a traditional shooter to play (like Black Ops, etc.), then try Splinter Cell. It's worth it.