The best sites for me are:
Poloniex - They are one of the best trading site and they are doing their best to maintain their reputation and they always maintaining good amount of coins and only limited based on their activeness.
Bittrex - Most of the new legit coins are getting here which give you advantage to buy it on an early age.
Yobit - A lot of coins to choose from, if you know how the whales move then you are going to make a lot of profit.
I agree with your list and description. So far,Poloniex is good and neat to trade. Very many traders and transaction are fast,just be very careful and vigilant because you may lost very fast too. Bittrex, I like it because many big traders also, and the the one that I like is that it has no trollbox, whales and speculators cannot dictate nor induced FUD.
Of course, I understand your choice in terms of Poloniex. Of course this exchange deserves the understanding and approval of users. But I do not understand why people do not sing such circumstances that occurred on Bitfinex. Because I'm not the only one who was shocked by what was happening last summer.