Poloniex doesn't have anything special like more trust, but they do have better trading engines and things like margin trading and lending makes it a completely different exchange with such features and if it goes down, then why won't people migrate to others???
well you could say thay have something special... first... they dont have coin votes so you cannot buy a shitcoin in with few btc. Second they are most likely always the first exchange to add innovatives coins with new codebases... where other exchanges struggled with
So, you want to say that they are too special that even those innovative coins don't get pumped on their exchange???
They ain't special in my eyes, I do trade there but they are not special... Even they got attacks and were almost gone during March...
But yeah, I do believe that they do have special security for their users to protect their funds and not get ripped...