metagamerscore uses RA(and just about everything else), so does completionist, but completionist is steam and RA only.
Hmm, metagamerscore is interesting since you can link your MMO accounts and whatnot, but the interface seems pretty confusing. It's got the old-nostalgic-forum-feel to it which I haven't seen in probably a decade
Just signed up and linked everything. It will probably take a day or two to get used to the interface but so far I like it! Hope it picks up some traction.
Edit: I forgot about HowLongToBeat. Great website. I use that for almost every single new game I start playing, although I haven't actually submitted any data to it yet. I also used to use GameFAQs for their difficulty, time to beat, and overall rating trackers which I did submit for a few times, but that site definitely isn't as active as it once was.