I think it is really important to check the wallet status on any exchange before you do a transaction. If the wallet is under maintenance you will see problems withdrawing at that point, transactions will get stuck and need manual attention from the staff of the exchange (that are always busy keeping things running)  Do a test transaction first, small amount to see if it works. I always do this with any coin despite of the withdraw fees. Better to have 20 coins stuck there then having 1000 stuck