gentle, do you know anyone who has withdrawn and deposited large amounts at gemini or itbit? Also what has been your experience or others with GDAX, i believe the trading is free? Isnt it part of coinbase?
I'm not American so can't use either of those, but Gemini and Itbit are designed for large players so I assume they're set up for decent amounts. You certainly hear far fewer moans about Gemini than most places. Itbit is pretty mysterious in comparison so I'd stick to Gemini.
GDAX is Coinbase owned. Trading isn't free anywhere other than Japan these days.