Yes, ICO can be very rewarding, Darcrus ICO was sold at 2500sat in December,2016 the price is now above 6000sat,it even pass 9000sat few days ago but the issue with ICO is to find a credible ones to invest into, some people have been burnt investing in ICOs
ICO's can turn out to be quite profitable, but plenty of these ICO's have been nothing more than a disaster for people investing in them. It's a gamble with a super high risk that you must be willing to take. Especially when you consider that like 98% of all the ICO's are fake/scams. It's a plague. The only people that really benefit from this are the "developers" and the people close to them. It's just shocking to see that people are willing to flush their precious coins down the drain by "investing" in ICO's...