Pros: Highly detailed world, thought provoking story and lore, excellent stealth and RPG mechanics
Cons: Boss fights are horrible
1) It's a stealth-RPG released in 2011. It doesn't emphasize run-and-gun, you can't sprint around at 20 mph, therefore it bores the typical brain-dead gamer.
2) Graphics are dated. Graphics are the #1 priority for most people these days, soon they'll switch to watching tech demos.
All of that aside, Deus Ex: HR is one of the most interesting, thought-provoking, and detailed games in recent years, and it exceeds in pretty much every regard. It thrusts you into an immersive, highly detailed and interactive, deeply conflicted, and plausible future world that asks many questions about where technology will lead us, but doesn't give clear cut answers.
Not only is it thought provoking, but the blend of stealth action and role-playing is great. Choices matter and you'll often find yourself in really intense scenarios, for which the outcome is ultimately decided by the player. The dialogue/persuasion system is perhaps the best I've seen, and the stealth gameplay is among the best I've seen.
It's a must-buy for sure, which can't be said for 99% of games today. It's a shame I waited until it went on sale, but then again, they did announce a Director's Cut that will fix boss fights among other things. It might be worth waiting for.