Is Counter Strike: Source worth it for content only for gmod?

Thank you guys for your suggestions. I will just buy it when it goes on sale since i don't like the whole "get everything free, just search it and download it" mentality .Nothing against you guys, is more of a problem with my brother since he pirates a lot of games and likes to make fun of me when i buy a game and he just downloades it from thepyratebay. "And i got it for free because im smart and your a loser" he likes to say, heck, the only legit copy he has is gmod and that's only because i purchased a extra copy for him