I think the first thing you should ask yourself is where it is safest and most reliable, then what type of amounts are you going to buy or sell and with what frequency.

So wondering where is the cheapest should not be the priority. What you should do is know what your transaction volume will be and quantify it so on that decide whether it is worth taking into account security and trust over high fees.

So what you're asking is relevant according to the frequency of your cryptographic digital assets and the amounts involved. Take into account trust, security before a cheap fee.