Answer needed from altcoin experts
You do not need an experts advice it's pretty obvious Yobit and CCEX are two of the best trading flatform,had no problem depositing and withdrawing my funds,no to mention the many coins in their data base ..
But of course you need to experience trading on their flatform to prove it..
What do you mean by flatform? Are they related to altcoins by anyway? I expect more explanation from you.
If you're a day trader, poloniex and bittrex are good choices. If you're not all new releasing coins and want some quick profits by dumping into the first day of hitting exchanges, then yobit and c-cex are the best.