Wick is insanely tough, and he's great in h2h. However, Ip Man is a Master among Masters, as he's literally beat I don't know how many Masters of different disciplines in the 4 movies. He also shows insane strength(sends people flying, destroys objects by simply focusing pressure, etc...) and he's even got some wuxia powers and can jump'float from time to time.
On top of that, he's taken beatings from guys like Frank and Gunnery Sergeant Geddes who are massive even compared to Wick.
And he can/will fight dirty if necessary, breaking bones, going for eye gouges and crotch shots, etc...
How John is with guns, Ip is with pure fighting.