its better than gmod rp for sure
Different style of community honestly, but in terms of overall quality it is pound-for-pound (from what I experienced anyway) on a whole different level from the average Gmod experience. Not to say it probably doesn't come with its own fair share of shit anyway, or at least the community I was briefly in did, and as folks have said in pages past they still run into dumb shit.
The RP I had on MTA in the summer of 2017 was some of the best I've ever had anywhere because it felt so natural and real. Part of that was frankly that you had an
entire city to roleplay in regardless of how dated San Andreas as a game looks now, and part of it was probably the fact it was just IRL RP. The only thing is though I think the size and scale works against it because it is damn near mandatory that you should play with friends because otherwise getting in on anything seems like it would be a massive challenge. I've never had that on a HL2 server.
I think its just a general mentality thing overall though. I've rarely seen any retards on the level Gmod attracts.