Well in ICO you will get mostly presale bonus and that is sweet. 
But it is not unusual that some coins would have big dump after hitting exchange but on the other hands, some will never go lower than ICO prico, so it is hard to say in general.
But it is not unusual that some coins would have big dump after hitting exchange but on the other hands, some will never go lower than ICO prico, so it is hard to say in general.