What are the differences between a half Ghoul and a Ghoul other than having one human eye and a Ghoul eye?
According to wiki article, differences are close to minimal:


Only one eye becomes red;
They may have different smell than common ghouls;
They seem to be more powerful than common ghouls, particularly increasing their power while taking damage.


No other differences were ever noted during series, and last difference was not really elaborated so far.