I used Flexjobs for about a year. I probably could have found a position sooner, but I only applied to postings that I thought were a great fit for me and me for the job. I was recently hired for a 100% telecommuting, semi-flexible schedule, full-time with benefits position in the field of education.
I never ran into a scam or a hoax when applying to positions at Flexjobs.
The optional skills tests they offer helped to give me confidence in my abilities. It's not always easy to judge what your level of expertise is in a particular skill set. Their tests helped me understand my level of expertise as compared to other individuals. I had been undervaluing many of my skills.