Some ICO projects are selling out and they are making 10x on the exchages. For these projects, you better get your tokens during ICO, you won't be able to buy from ICO and then you can't also buy it from exchange due to extreme prices.
But it is almost impossible to distinguish which coins are going to go down or up after the ico, most of the time is going to be a matter of luck rather than skill, to me it seems the ico market is slowing down and most icos I have seen in the recent times drop in price after the ico so it seems the enthusiasm for this kind of investing is going down and it makes sense after all the regulation put in place in the last year.