The more exchanges the better. More competition will lead to better service and prices. Especially SERVICE is very much needed these days, I can speak from my experience with thousands of dollars gone missing for several days now because of an error in Poloniex systems. No support, nothing at all.
A good review/compare site for crypto exchanges would be useful also.
Got my coins back after some 4 days of silence. Very happy but Poloniex has work to do getting their systems working properly and a support department responding within a reasonable amount of time.