As far as i know, only etherdelta is the most safest of all exchange, but i suggest you to save and put your money in a wallet so that it will be kept because you cannot rely on any exchange in keeping your coins.
The recent hack does not prove this security but EtherDelta is a great platform, in relation to security, the hardware wallet is safer, because own you will own the key, exchanges only use to trade fast.
Many times hack try is happen on trading site and online wallets only so keeping large amount of fund in the any trading site is not advisable for anyone. However, better option in that etherdelta and livecoin website to use for trading and keeping some funds in it.
Keep convert the Cryptos as price grows on the concern coin. That will allow you to find the profit more than you expected.