It's better to buy later on exchanges especiall nowadays markets are all red and some ico offers a large amount of bounties so expect a big dump
Yes buying later is good nowadays but only in those ICO which are of an average potential about the price increase in the future for example there are some ICO about which we cannot estimate that how much will the price of it increase but there are some ICOs which have a high potential such as MB8Coin as it is a running business and the demand is already in the market so the price of it will increase much higher in the future if anyone will buy it in ICO then he will be lucky.