Public college is better than private college,can I say that?

You can say it, but it wouldn't be true. Some private universities are much better than the average public one; some public universities are much better than private ones. It all depends on which schools you're comparing. For instance, the "Ivy League" universities are all considered to be excellent, but some are public, and some are private. You just can't really make a blanket statement about ALL public or private institutions.

Depends whether the degree is recognised a not - how well known is it

everyone is entitled to their own opinion - i agree with that statement