The technology stack you are using is not going to affect the chance of getting into the network. Once you have gone through the screening process, you're will be matched by a team of engineers to prospective clients based on your tech stack, availability, time zone and other factors as well.

When it comes to technologies being in demand, it really ranges all across the board: from the standard PHP, Ruby, Javascript etc, over more bleeding edge like React, React Native to niche things like OpenCV are all there.

Full disclosure: I am currently employed as Head of Community for EMEA @ Toptal

Hei there, I am just reading up and I think it's extremely unfortunate. Luckily, I have witnessed different experiences. I especially appreciate that they are running an internal Slack where community members are supporting each other and several Toptal employees are usually available for feedback on job applications one has currently running. Regarding rates, I cannot complain, eastern European here as well :)

If you are looking for a steady stream of high quality freelance gigs and do not want to worry about billing, hunting for clients and other headaches you encounter as a freelancer, then you should definitely check out http://toptal.com

The best part of it is that it has a sprawling community of freelancers all over the globe who are happy to help whenever you need it and if by any chance you happen to end up having holidays somewhere, there is a huge chance that there are some Toptalers right around the corner happy to take you out for drinks and give you some insider tips on the location.

Full disclaimer: I work with Toptal at the moment and am pretty happy to be there :)