I've received that email from bittrex too, but my amount is too small to be withdrawn! I want indeed move away from bittrex, it would cost me their fees, but the sad fact is that I can't because for many of the wallets I am under their withdrawal threshold (3 times the fee, it seems to be). I don't like the idea to have to deposit there more just to be able to withdraw (all the required "movements" would cost me even more!)
What do experienced traders suggest? (Ok, likely experienced traders haven't this issue of having too few of a currency to withdraw…)