I've worked as a developer through oDesk and I also hired developer to do a little bit of work for me through oDesk. When working as a developer on oDesk there was more than one occasion where I was hired to either finish something that another oDesk contractor didn't finish, or fix something that wasn't written quite right. The code that I had to work with from the previous developers was always pretty sloppy and never commented and it looked thrown together.

When I hired a developer I got good results. The developer came in way under the amount of time that he quoted, and the code was very clean & commented.

I believe that the difference was that I hired someone based on their skills and the interview where the people who I did work for had initially hired based on lowest price and they got what they paid for. You'll find that the lower priced devs are usually a group of people or a company who is pumping out code as quickly and are more worried about quantity than quality.