I have seen a lot of fails, the successes are yet to be determined actually. The reason ICOs fail are many. For me one of the main ones is not having a tangible product or service already, something like a prototype. Most just draft a whitepaper and buy a designer with cool artwork, that's it. Also having a great dedicated team of both technical and social expertise goes a long way.. some projects overlook the importance of marketing - but then marketing has to be done at the correct time.
Another reason is having an overzealous discount program and airdrops. Once the ICO hits an exchange the freeloaders dump the coins thus sending the price to sub-satoshi levels.
My sig's coin MeVu has a great balance of all of these. Have a look.
I have many stories of success from the previous years as I entered in crypto world, I used to participate in bounty campaign and invest that ICO at the same time and mostly I always have earned good profit and bounty rewards will soon come to me after a few weeks at ICO end, but suddenly this year I was surprised because my happy moment last year was gone and all this time frustration is always come on me for I get nothing on most bounty I have participated this year.