The 47 Ronin
You should join me Kami its fun to play MMyup, sup... can take several months. CSS is casual. GO is, too, but there's been a lot of interest in competing. I haven't competed in over 10yrs, back when CAL/CPL was the top dog (before CAL-IM was added). Many of us are still on source because GO is too serious. The GO peeps play a lot of MM, though.