To this day I did not use in a very intensive manner their support service (I guess I had a message on each of them).
But without any hesitation, I would elect Poloniex as the best of the best :
- Because it has a trollbox, and though it can lead you to have a misinterpretation of the general feeling, you can have an instant access to instant answers from a very active staff. And you are free to not listening the trolls, you get banned quickly anyway.
- Because it has a much greater volume, which guarantees that your orders will get filled much faster.
- Because it offers P2P loans.
- Because it offers simple yet damn useful analysis tools of your trades.
However Bittrex still has some nice advantages too, such as much more trading tools or more important some very important crypto-currencies missing on Poloniex (Waves as for exemple).
So even though both have advantages over the other one, Poloniex is still the best mainly for its volume.
No trollbox for at least a few weeks now...