Vantaggi
Simera basically manages a talent pool of candidates (which includes you) and they find pretty amazing remote jobs for you, based on your skills and preference. Once recruited, you'll work with the new company but always through simera, which does a great job at checking up on you from time to time and making sure you're enjoying the job and it fits your needs. The salaries are good compared to what I would find locally in my country (Guatemala), always on time, and they take care of finding the job for you. They are also quick to answer your questions and keep communication open all the time, which is a plus.
Svantaggi
I've been with Simera for about 1 year, and at the moment I do not really have anything negative to say. I cannot speak for others, but in my experience so far it has been pleasant working both with Simera and the company I work with (through Simera).