I believe that HobbyWing build Speed Passion, Venom, Yeah Racing and one or two others, the difference being component quality (on some of the higher-end models/brands) and branding in general. In general, though, it seems like pretty good quality stuff. I don't think HobbyWing is sold as a brand outside of China, but eBay is your friend...
I have the EZRun 5.5T and 60A ESC in a 4WD Durga and will probably get the 9T motor/ESC combo for a budget 2WD car too (less than £50 delivered...)