On the one hand I would never submit my personal informations for eg. bounties or airdrops. Chances are high that the info will be missused. On the other it may actually be a good sign if an ICO requires KYC, especially if there is a aerious, long lasting company behind the ICO.
Don't quite understand how it is may actually be a good sign.
Absolutely not important so serious company looks from the outside. Even if you spent time researching it and found it appropriate there is always a chance that you will fall for scammers.