Poloneix is the most legit exchange as far as i know.
It has more user friendly options.
If you want to buy newly released coins,then Bittrex is the best exchange as it has more newly released coins listed.
Except,their coin manipulation is the highest I've seen.Don't get me wrong,I'm a daily trader at poloniex,I even invest in the most newly listed coins but when they start manipulating things,you will be surprised how they've control over everything you wish to do.To make it more simple,remember the lags and still the coin sells ? They do it on purpose.