which one is best?

[CoinStar1337]

I'd say Bittrex, but I recommend you use a variety (of the trusted exchanges out there).

Here are my top 3 Exchanges
https://www.youtube.com/embed/231uxYom5dA

[Nahl]

i just share my experience use these exchange that since 2014 i had never any issue regarding my account and in my point of view that both are the best exchanges with good positive feedback but indeed poloniex had more huge volume support for altcoin than bittrex

[concept2]

Poloniex has a larger trading volume but Bittrex has a larger variety of coins.  It's your preference or do both.

Too many scam accusations against poloniex and therefore, I do not like it at all. Only the margin is a special service on poloniex which bittrex does not have

[Babayega31]

Poloniex has a larger trading volume but Bittrex has a larger variety of coins.  It's your preference or do both.

Too many scam accusations against poloniex and therefore, I do not like it at all. Only the margin is a special service on poloniex which bittrex does not have

Nope i think there's No scam accusation in poloniex but instead their system are quitely got an error on these past days and that one is been mocking up by the people who used to trade in their, But all things are been fix right now and I trust this exchange rather than any other who have shit service and yet still existing on their ecosystem.

[Cactushrt]

It depends on what you are using poloniex is a mobile friendly platform but there are so many complaints about the site so right now i am trading on bittrex no problem at all.

[zulkarnaen]

I think either bittrex or poloniex have a good reputation, because in this exchanger is available big coin coins that have good potential and deserve to be traded, so here we can have a chance to profit from coin coins we trade

[camelson]

which one is best for trading alt coins? poloniex or bittrex?  

Both of them are the good exchanges to trade on. They both have high trading volume but on poloniex there are only few coin listed while bittrex support more coin than poloniex. And also the verification time on bittrex is less.

[linkybit]

I like poloniex and kraken, both are good one.