I'm about 20 hours into Deus Ex: Human Revolution and I've got to say that I'm very impressed. It has an immersive story that keeps you engaged, and mostly interesting side quests that aren't simple "go get this item for me".
There are some drawbacks to the game as I've found that this is one of those rare titles that makes me feel a little nauseous to to the movement of the main character. The bouncing up and down while he walks bothers me. Don't get me wrong, it certainly looks realistic, but I might puke. That was actually that biggest thing that kept me from giving it a 5/5.
The other issues I have are that the designers seem to have made the game too hard to do in a stealthy manner. Even in a place like a police station where I certainly had no intention of mass murdering former colleagues, after about an hour of trying differening route and methods, I just killed them.
Bottom line is that this is a great game and definitely worth a purchase. Especially given the current game landscape. Come on November!