You can set whatever rate you want. You can set 1000$/h, but of course, no one will hire you. Anyhow, my rate on Toptal is much higher than what I could get as a senior dev in my country, so it is good for us and as I can tell from reviews much of the world. Devs from the USA complain but from what I can see there are still many devs on Toptal from the USA and many Toptal events in the USA. So to each, it`s own. Another good thing is that you can be part of Toptal and have it be a backup source of work. You can choose your availability without any penalties. As for the companies/clients of Toptal. They get tested devs, guidance (for inexperienced clients) and they have mediators (Toptal) who would guarantee the quality of the devs and intervene in the case of a problem. It is best rated freelance platform, for a reason.