Hello,
I bought my first MBP in 2006 (November), a second in 2009 (June), and this current one in 2011 (November). In that time it's been my only computer, and I've played thousands of hours of games, including most major releases (e.g. Battlefield, Bioshock, Stalker, Call of Duty, Company of Heroes, Shogun Total War, The Witcher, Tomb Raider, etc.)
My first computer was problem-free; my second got a loose fan (a simple repair), but unfortunately the Nvidia graphics card was faulty and at the end made the screen turn people. This current one had its Hard Drive die 6 months ago, but remember we are talking 4 years of daily, continuous and extensive use. Not a bad record? I always used Windows-Bootcamp, but since I got the SSD put in I only game on OS X.
Ultimately I think it's about expectations. These computers are expensive and should be held to a high standard. If the computer died because you played a game for 2 hours at night then you have a bad product from a bad company; but Apple, as much as they irritate me sometimes, are not a bad company, and their products are not bad products.
More and more games are on OS X, and this is a good thing. One problem is the poor driver support. Another is underclocked graphics cards that further throttle themselves when in intensive use. I'm not certain if the current model is affected, but I don't think I ever noticed it on any of mine.
Steve Jobs never cared about games, and this legacy is largely continued. Unfortunately many customers have some-sort of Stockholm Syndrome and now just accept that "Macs aren't good for games".
Yet there is no particular reason to think this. A typical response is that you should build a gaming PC, because gamers need the most expensive stuff to render the best visuals. But the Steam hardware survey shows that most gamers have only average hardware and upgrade in around 4 year cycles. Another suggestion is to buy a console. But consoles, even at release, do not have exceptional hardware, and so most games still look and run better on a computer. Many AAA games upon release (Fear, Stalker, Crysis, etc) were unable to be played at high resolutions even with the best hardware. It's unrealistic to expect a laptop like the MBP to be able to run new games at high resolutions and high detail. But the point is, this is an unrealistic expectation for most gamers.
TL; DR
So go ahead and play all the games you want. Keep the power plugged in if you can, and the computer cool too. If the game is slow, turn down some settings. (Shadows, Anti-aliasing, and SSAO especially).
Don't forget to have fun.
My Steam profile: (remember I play non-Steam games too).
http://steamcommunity.com/id/gregith/games/?tab=all
