I used to list my design portfolio through Elance and bid on projects. The feature I hate about them is they are very expensive for designers, writers and programmers, etc to get work through. Guru ... I hate most everything about it as a designer. Their prices have increased and when I was there, each project got so many bids that the buyers were overwhelmed and abandoned the projects instead of awarding them. Elance has a high rate of buyers posting projects and not awarding them.
As a buyer, I've used Scriptlance a lot and got my money's worth every time. I've never been a provider for Scriptlance so I don't know what the drawbacks are.
It's hard to compete with Elance. They spend millions of dollars on Google Adwords each year. Guru comes in second and then there's all the rest.