ICO and IEO is a good way to crowdfund ofcourse, ICO especially is already tested by the whole community since years ago, though the community have the public secret that ICO sometimes is messed up, often leaving their investors in a grey area full of uncertainty. IEO in the other hand is provided by a popular exchange to facilitate any new project that will be coming up with a new idea. By that we could see that IEO could be more legit than ICO itself however there's still some risks involved whether the project will follow the roadmap or delivering what they promise.
However, as you can see it's always better to seek for something with more certainty, with existing product and not just empty handed but with plenty of proof like VEIL and that's why it's my favorite.
VEIL is basically integrating best-in-class anonymity technologies to become the first cryptocurrency that provides uncompromising, always-on privacy. they already have a crystal clear vision and product. Also there's no kind of BS overfunded crowdfunding nor premine and what's even more promising is the fact that it's already traded exchanges with quite of the volume
If I were to choose I'd certainly go with the legit ones instead of putting money into something like IEO and ICO like what most of smart people do, heck even millionaire is putting their money in a project that already starts to surface not just an idea right? so that's my 2 cents I guess that's the best thing I could think.