If there's no option investing into ICO is fine, however if there's option I'd definitely choose altcoin, I mean it's like no brainer to choose a coin with CLEAR background with working product or atleast progressing than only an idea that's simply out of thin air. I mean bringing up idea is good but not every idea will come to realization but altcoin is the finished product of the realization of that product.
Simply put example, my current favourite is VEIL that's integrating best-in-class anonymity technologies to become the first cryptocurrency that provides uncompromising, always-on privacy. There's no chance of being those kind overfunded ICO that only aim for money since it never opened ICO phase nor premine neither, even better VEIL is already traded on exchanges with quite of the volume.
I think that people really should not be putting their money into ICO, it's always better to choose altcoin, ICO can be interesting and having big potential but altcoin is also the same, among many there'll be some with huge potential like VEIL so I think that choosing altcoin is wisest.