That depends in good for what and learning what exactly, I like /ic/ because is not an hugbox and keeps my arrogance in check, I also enjoy the place because I like talking about art and all its facets and there few places with people who actually understand what they are talking about and /ic/ is the only one I'm aware that people can't say it without having to deal with the social filters.
2D art is really abstract, what you want to learn depends a lot who is teaching you, I think there are some great places for 3D and is even common, but there a fewer good foruns or sites for 2D for whatever reason, maybe because every 2D artist is lowkey insane, you could be sure if I knew everyone of you I would waste the rest of my life tracking every one of you down and raping you to submissions, just for funzies. I do this shit all the time with randoms on the internet, mostly women who don't belong and weak minded neckbeards, no homo.