Just thought I'd throw my two cents in as I've seen it mentioned a few times now, Rev is not worth the effort anymore. I've worked with them for 5 years and whereas it used to be a pretty good source of income, those days are gone. The audio quality of the vast majority of files are dire (so even if there is a queue full of files to be worked on, it takes ages to find one that is workable), the pay for the majority of files is insulting (0.35 cents per audio minute - following a recent "pay rise" from the base rate - though they have since started calling it "standard rate" of 0.30 - which means that you could potentially spend basically all day working on an hour long file and get $21 for it - not forgetting you'll lose about a quarter of that in the exchange rate). When you start out, especially if you haven't done transcription before, you will be slow (no matter what your typing speed usually is) so it will take a long time before you make anywhere near decent money, even if you can find decent files, and even as you get quicker, the pay means the majority of the time, it's just not worth the effort. There is slightly better pay on some files in "Plus" (there are three categories, Rookie, Revver, and Revver Plus), though the majority of the time it is still not great, but getting into Plus is very difficult as you have to keep up your minutes, which is hard when there's not many workable files around. There are currently people that have been in Plus for years - myself included - that are going to drop out because there just isn't the work to maintain the minutes.
Over the last six months, they have lost so many people that had worked with them for years because they have been treating everyone terribly - mostly there is no communication, when they do communicate, they only respond selectively and ignore most of the responses/worries/issues. They fired all but one of the team whose job it was to actually communicate with the freelancers. They have made it abundantly clear that they do not care about the people that are working with them.
There is a lot more I could say but don't want to ramble on, but they are just not worth the effort anymore. A few years ago, I would have recommended them but now, you would be better off finding someone else. There are some good points to working with them but the bad far, far outweighs the good at the moment, and you would be hard pushed to make a decent amount of money, even if you put in long hours.
Just a word of warning about WWW too (though I have limited experience with them as I was put off by a very rude email from one of the onboarding team), if you aren't active for a while, they will deactivate your account and you have to go through the onboarding process for returning transcribers (though I don't know what that involves as I haven't bothered). It's probably only worth applying there if you are planning to be very consistent with the work you're doing for them.