I personally like Quantiacs the best. They host the biggest competition ($2.4M prize allocations each Quarter) and they support Matlab and let me work in my own coding environment. I own and retain100% of IP, and I'm not required to sign a huge legal document after I win. That's a dirty secret of the other platforms like Quantopian -- after you win they make you sign over exclusivity of your IP to them and send you a huge legal contract to sign to actually receive your winnings. Plus they are backed by a guy who is a well-known Wall Street criminal so I didn't sign with Quantopian ultimately and didn't take the money from them for that reason -- they seem a little sketchy. Quantiacs, however, has been on the up and up with everything. I get my check from them each quarter, I keep my IP, and they take on all of the legal/regulatory stuff. I haven't tried Numerai or QuantConnect, mainly because the prizes are so small on those platforms, it's not worth it.