Having an exchange stands out as an intermediary, which is the only difference between IEO and ICO. So, if the exchange is unreliable, that IEO is also unreliable too. In my opinion, you should choose reputable exchanges like Binance to search for IEO and invest in it.
Agree, as long as the tokens sales exchangers are highly reputed exchangers such as Binance, Huobi or Okex, then it is certain that the project undertaken is a good project and has the potential to give profit to the IEO participants.