I use both pretty regularly, I prefer RYM for the reviews/ratings and genres/descriptors they tack onto the albums which I think are cool. MA is good because of the similar artist feature, which I personally find mote thorough and accurate than lastfm, and branching off into obscure stuff. Musician and label pages are also cool.

RYM is the better site most definitely, but I still enjoy MA.

I wish there was something like Encyclopedia Metallum for both Punk and Metal. They should be united, Crossover forever.

I don't think I listen to any blues at all

I'm working on a grunge one. Grunge is metal and punk. Same thing :D

Kidding. But seriously, I do run a small grunge wiki.

Post it. I want to find a way to ruin it for you.

They're not even close to being similar.

Does it include stuff like the Wipers, Flipper, and stuff? It'd have to, I can't see a grunge database being that large

They're opposites that (their extreme counterparts) have a few simialarities which work well together. It's like yin and yang.

Oh look, you want your genre to remain pure and undiluted by other genres. Cause punk doesn't have a sound for metal to ruin.

Yeah, and it sounds like punk mixed with metal. Cause punk has a sound.