First i though about Elance and Odesk. I've already hired there for other little jobs and i was satisfied. Now i need someone for a 4 months job. On these platforms I found some great developers from all over the world with low hourly cost (10$-20$), high rating (most of them between 4.7 and 5.0 over 5) and high earnings (over 100K$).
Therefore i thought "wow, that's awesome!"
But...after some research i found out most of them are scammers or incompetent. They deliver the job unfinished, full of bugs and out of schedule and the reviews are fake. The web is full of complaints for most of them, especially from India.
Hence i realized it's impossible to distinguish between honest and scammers on these platforms. I've got a project to finish within 4 months, and i really don't know where to find competent people and avoid scams.