Counter Strike Source is amazing with its simplistic, yet realistic gameplay which causes some tense and awesome moments. I have owned this for just over two weeks and in the 30 or so hours which I have played it has been amazing, with CS_OFFICE being my favourite map. If you like Shooters which are in some ways realistic then this is the game for you. So this game is definately highly recommended by me.
Steam Achievements are also incorporated with this game to moniter your Kill: Death Ratio and Map Win: Loss ratio along with many other things which keeps making you want to come back and make those statistics better so that your friends don't think that you suck.
Thank You for reading this review and I hope that you enjoyed reading it. :) Thanks