You can sometimes find talented people on sites like that. Years ago, I used a similar site that was just for Voiceover actors, and found a guy that did an outstanding job on my project for very cheap! He was A++++ ability.
Here's the problem:
Often, the people on these sites are not professional. I don't mean that as an insult, it's just that they don't have an up-and-running factory for doing this work full-time. They tend to try it for a few months and then go do something else and never respond again.
That is why I always look for these qualities:
1. Has this person been doing this job / service for a LONG time?
2. Do they do it regularly? Is it their main source of income?
3. Is the quality / their ability very high?
4. Are they super-responsive and organized?
The answer, if you're looking on those low-balling sites (or Craigslist) is almost always NO. Otherwise they'd be doing their work somewhere else and making real money.
Still, you can find the occasional gem!
Punchline: that amazing voiceactor guy I found on that site? He disappeared after doing my project and never responded again. :)
Carl King[br]GuitarTricks Video Director / Producer