I used poloniex for about a year and dug them, but apparently crypto is like life and the true test of a person or an exchange is what happens when something goes wrong. When something goes wrong at poloniex it's a nightmare. Their help system never updates and frequently takes months to return your coin if there is a problem. When more than .8 of my bitcoin disappeared one day I started trying to contact them every conceivable way. All the while the value of bitcoin plummeted. When they finally restored it there was no compensation of any kind. So I got my money out, made sure the transfer went through, and then submitted a ticket to close my account.
In two minutes it was closed.
Binance, where I transferred my funds and continue to trade had a problem last night. The whole website shut down. Every half hour they tweeted updates and their CEO stayed up all night to make sure that the problem was fixed. Now that is customer service.
Poloniex was great... until it wasn't. I miss having the ability to lend out my coin and earn interest on it for their margin trading program. But it just isn't worth the anxiety. Eventually you could have a problem as big as mine, and when/if that happens you'll see how frustrating it feels to be ignored.
If customer service is important to you I recommend that you sign up with binance.