I would not call all of them the same because they are here because they are an improvement to the previous one. IEO are exchange hosted ICO while STO are ICO/IEO that provides the profit as dividend directly to the holders. So, they are not all the same.
The user experience has improved a lot from ICO to IEO and we would see more improvements on experience and security in the future.
They all have their uniqueness, that is well understood. However, which among them will you consider the best?
Personally, I think IEO has more benefit than the rest.
tsaroz, can you personally take a look at this MPCX IEO details on OOOBTC and give me your professional view on the project. I will really appreciate that a lot.