The most important thing you need to pay attention to when choosing an exchange for trading is security and interface. It is also important to determine the amount of Commission that is charged for transactions. And of course, support for developers and quick resolution of problems, if they arise. This is what is most important to me in any exchange.
Actually, I have not yet met such a trading platform that would take higher interest rates from participants or raise prices for transactions. In any case, most traders have large volumes of trades, at least more than $ 100 or $ 200, and therefore prices per transaction suit everyone. I am more interested in questions on the time of transfer of funds from the wallet to the balance of the exchange or withdrawal of funds from the exchange.
Of course there are some exchanges that still have not corrected the capabilities of their users. As an example, you can bring Hot Bit, which is still raw, because there are difficulties in accessing your account, as well as in crediting funds to the balance.