i want to ask will it be better to invest in an ICO that already has a product or an ICO without product not yet finished ?
Its always better to invest in an ICO which has practical use to it. There are some like Social, which is based on social media. KickICO, based on crowd funding of other ventures, Snapup, for buying. Most of them in the top selling ICO's right now.
Yes your right, in investing in an ICO you should have the proper background of the ICO that you are planning to enter. Because if you want to earn a big profit you should be wise in your decision. Because some investor are being pooled by the ICO scam and that just wasting money and time.
The important thing is be careful on what ICO your going to trust.