I use bittrex for trading altcoins. Till now not faced any big issue there. Binance is also good in terms of trading or deposit/withdrawal fund. I also like etherdelta because its a smart contract & de-centralized exchange, no need to worry for deposit & withdrawal fund but etherdelata little complex & slow. For margin trading I use BitMex, its amazing. Sometime you get double or more than that but sometime you get liquidated. I can say them good exchanges instead of best exchange. Hope in future, we get some better de-centralized exchanges as lot of experiments are going on.

I choose option - Can't Say. However i feel that Ethereum is a powerful coin having uses, community, technology etc which may lead its price go high. For long time its price is stable. Many ethereum holders sold ethereum and buy bitcoin/BCH or other altcoin. As per my though, there may be a good chance for ethereum to cross $500 

Bitcoin is the King. Pumping will get down shortly and Bitcoin again will rise slowly to a new ATH.