The practicality is that the pay is pretty low - at least till you can make it to rev+ which is basically where you've done a lot of minutes in the last 3 months and have good ratings. Then you get the pick of the jobs, so the plus members snaffle up all the nice files and the potato quality audio is left for the rest of the folk. These can be hard in a lot of cases, but I'd recommend using the preview option and also using time in your first hour (where you can unclaim the job penalty free) to scan parts of the file if possible so that if it becomes hellish you can bail. That being said, that tactic does essentially increase the chance you're not being paid for the time you spend involved in the work (not actively transcribing but assessing a job).
I've done it a bit and consider myself likely to return if other avenues dry up online or I'm curious enough to review the offerings. The best bet - if you enjoy the work at least - is probably to graft a lot for the first couple months, get up to plus then maintain your figures and retain the pick of the bunch.
Oh, btw, for anyone working there - remember your text expanders! They're like autocomplete that you set up for words you're typing often and they will really help up your transcription speed.
Last couple of points - adding an audio booster tends to help. You can get some as chrome extensions, others are stand alone software. The (rev) forum is your friend if stuck - people are kind and will help if they can.
Good luck all x