I'm guessing a few folk here use GDAX - I haven't used it before but thinking about it. Are there any issues I should know about? Specifically, I'm wondering about any issues withdrawing BTC, withdrawing $USD, and whether they do SEPA transfers? I haven't used an exchange based in USA before (I'm in UK) and would prefer the opinions of this community before going ahead. Thanks y'all.
Nothing anything I am aware of. You should just be 100% sure that you are fully verified. GDAX also tends to freeze an account from time to time if a larger withdrawal happens AND you should know that GDAX is currently handing out information about US citizens (not sure if all nations), which traded more than $10-15k?!
Why not using bitstamp instead ? Some features but based in UK