I've been trading on Poloniex for months and not had any issues. But with the substantial increase in users, Poloniex is unusably slow to make trades. Rates are changing multiple times every second and it takes over 10 seconds to place my buy/sell bid. In those few seconds, the price has already changed and it is impossible to make a bid.
I am looking for alternative exchanges which has had a good track record and works without these delays. Also, it should work on mobile. Any suggestions?
That's how heavy the volumes is established in Poloniex everyday meaning there are really lots of traders using this platform and increasing more day by day.
I can't say any of the alternatives since I don't know if other altcoin exchanges will not be like the status of Poloniex today when in some of the cases they will be the one experiencing this big loads of volumes everyday. Just give it a shot for other exchanges and see if it will meet your expectations.