Bittrex, without any warning, turned off withdrawals on accounts that did not submit KYC then demanded photocopies of drivers licenses and photos of clients to allow them to get their money out. This is extremely shady if not outright theft because many people are unwilling to do this. They effectively stole some of my money by doing this. Some Russian hacker was able to get access to their KYC photos as well, as they apparently have poor security.
Poloniex was always a good experience for me, but they stopped serving my state and they started demanding KYC for new accounts, so old accounts are probably next. I was using them with a VPN for awhile but it's too risky so I exited.
Seeing a lot of traders moving to Binance, probably because of KYC. American exchanges are probably best avoided if possible. Never leave your money on exchanges for long.