I truly think that the most powerful blockchain is the one bitcoin has, since it is the biggest and probably most supported one. However, one can't create a token there and the platform is not very friendly to changes. That's why I would still choose eth for icos, even though there are certain problems with this one. If not eth then neo. I think that it better be a strong powerful platform if we are to create an ico on it, because otherwise we can make a big project that will die, because the platform was not big enough for it.