Yes IEO is still the favorite for now because with IEO we can more easily do overall research. In addition, on the bright side, we can know which exchange the project will launch, because if the exchange does not have good capabilities, it will certainly reduce enthusiasts.
Are you kidding me or what,,, I remember all too well the first few IEOs that came out on Binance and Bittrex and trust me, they were not easy to research. Other than the links on official website and the PR and paid sponsored articles, there was just as little information about them as any plain ICOs.
Look at Binance Launchpad and Bittrex IEO platform projects and see where they are today.