Well if there is such a thing as proven reliability in a segment where the tech moves so fast I don't know, but I could recommend the Crucial MX100 series. They've been out for a while and I haven't seen any issues, and can be found at fairly low prices. The recently released successor MX200 series haven't proven to much better performers either. I wouldn't hesitate to bet on the Samsung 850 Evo for myself, especially for a system drive. But I just so happen to have three 512GB MX100 for games and storage and they've been behaving themselves.
In truth, no single drive is ever to be considered truly reliable.
Throwing the last mechanical drive out of my main system was the nicest upgrade I've done in a while.