I'd say Bitmex is currently the #1 for Bitcoin futures trading.
I second that. If you are going to trade futures, there's no better exchange. Here is a nice list of bitcoin futures exchanges
http://www.bestbitcoinexchange.net/futures/with an overview of their pros and cons, trading fees, types of trading, etc. Still, I would stick with bitmex.
In my opinion, popular and trusted exchange is-
- Binance
- bittrex
- poloniex
I use bittrex for tradeing
You can't trade futures on those exchanges.
Binance, for example, plans to include
futures trading in the near future, along with margin trading, DEX, and some other features.