Medicore Game, Not Bad If On Sale
Cards on the table first, I am a Bond fan, but a hardcore gamer, too.
On release, this game got mediocre reviews, and the game can only get worse with time as standards get better. It's surprising that Treyarch went from this to the much-lauded Call of Duty: Black Ops (which I haven't played, but looks miles better than Quantum).
The graphics weren't even that good for the time, but they do the job. I actually found the weapons quite satisfying, and the stealth system to be pretty fun. Another plus point is they bothered to get the main actors from both Daniel Craig Bond movies to voice the game. So the single player campaign is pretty fun, but pales in comparison to other games in the genre.
There are still people playing multiplayer, but this long after release (about 2 or 3 years), it'll be an uphill struggle for newcomers, as it's likely all the other players know all the maps by heart. That's certainly how I felt when I gave it a try. It's not like the multiplayer component ever lit the gaming world on fire, anyway.
This is a hard game to recommend over other superior releases. Even the over-rated Modern Warfare (which you can also get in bargain bins now and came out around the same time) is better than this. But it's a fun little game if you really want to take the plunge.