as per my observation and experience, i find odesk the best platform to get online job or to get your work done online. You are right, there are some issues with fake clients, but this is what happens when you work Online.
About tests, yes they are important, but again it depends what type of tests you have given and what type of test your Employer is looking for.
Odesk is the best.Nothing can be compared with odesk.But i heard that elance.com is a popular site for the freelancers.I have a account there.Odesk delete fake client cause they post a job bt they dont hire anyone.they make the workers frustrated.
I not get any project from odesk on my profile, is true. There can be reasons because I not worked so much for my odesk profile, I have my company profiles on odesk and I work from those different profiles and our company not get any problem from odesk.