I played at Nitro for several years, but I stopped last year. Do you have specific questions?
They were fine for me for the most part, but I read a lot of stories about people getting their accounts locked for trivial things. It's also really annoying to have to do BTC conversion to get your bets in with how fast some markets can move, you're often going to be missing the advantage of good numbers just doing math or volatility with BTC price while you wait to move funds around.
Not enough advantages to offset the risk if you have other options IMO