Binance market in my opinion is very good because it has the biggest users right now, and for good altcoins for investment like eth, bnb, link, dot, xlm are still very good to buy, maybe you can find out better than this.
Binance has more appealing term with the low transaction for all coins, it also allow many fiat to cryptocurrency exchange that encourage more fund on the exchange. Have been actively trading on binance for few months now and I wondered why I got on it that late. If there is any wash trading on the exchange,it is not noticeable. I feel possession of bitcoin should be lowered now into altcoins, ethereum should lead the highest possession of altcoins in the portfolio.
So now you decided to sell off most of your Bitcoin when it's actually dropping? I don't care about your money but you might be in a loss here since the Bitcoin bull run is about to happen soon. It's better to accumulate more of it than to sell some of it. And don't forget to diversify your money, I'd better buy more ETH than any unusual altcoins since the most promising altcoins are on the top list.