Depending on what currency you are going to trade. Not all exchanges have this or that coin. For example, I used the exchange as -
https://www.cryptopia.co.nz/Homehttps://exmo.com/https://www.binance.comI had no problems with them And a couple of times there were delays.And in General everything is fine. You can also read the reviews and on this basis to conclude which exchange to work with.