There are pros and cons if you buy during a initial coin offering and if you buy during exchange already. ICO is great because you can received bonuses and discount. The only problem is when the ICO did not reach the target investment and your investment is in trouble. Now, exchange resolve the issue about the project since it already able to reach the exchange, the only thing is, most token increase during the exchange period higher than the ICO price. No discount or bonuses whatsoever. But there are a lot of times that exchange price is lower than ICO then that is a good buy. If you believe in the project then go ahead. Pick any option, you're in track.