Well personally I used to use Bittrex as because it was easy and efficient but to be honest whenever I used to send my Steem over there I had to exchange it to BTC or altcoins and than transfer them to another wallet so that I can exchange it to my local currency. The transaction fees was an issue for me.
While the transaction fees are much higher in exchanges so it was kind of a loss and time consuming as well. Whenever I wanted to get the price that I want I had to keep it on trade and wait for it to go off. Well this was going on for some time.
After that, I started using Blocktrades.us while it is surprisingly cool because the price is on the market value whenever I exchange and I do not have to worry about trading it , so as a matter I just send my Steem to Blocktrades and get the Coins that I want in my other account and sell them for fiat.
It is easy and effective as well.
I prefer Blocktrades because it's simple and fast, I don't like logging in to exchanges. I just choose my currency, put in an address and send my STEEM or SBD, without waiting much. The exchange rates are amazingly accurate and fees are based on network conditions of the currency you chose. BCH, DOGE and DASH gave me amazingly cheap cashouts.
There's also the fact that this customer service was quick to respond when I made a mistake.
@blocktrades is my personal favorite.
To trade STEEM to SBD you can use the internal market or bittrex. The internal market has no fees contrary to bittrex, but since the volume is much lower the exchange rate is sometimes worse. It is, however, the easiest way to change SBD to STEEM and vice-versa.
For trading STEEM to Bitcoin, Binance, Poloniex and Bittrex offer this, but only the latter has working wallets most of the time.