one thing to consider, which happened with bch, was those that left their btc on bittrex were able to exchange their bch right away when the prices were high. i had my btc in my electrum wallet and it seemed like it took forever to get them on the exchange. i think that was due to the high difficulty from the btc blockchain, and i don't think that will be the case with this new blockchain. also i'm skeptical of bittrex's trustworthiness now and will only use it for small amounts, so i will continue to keep btc in my private wallet.