The Wookie was also in that film once.
I think the Yeti looks a fun type of guy, even if mildly anti-social. The Wookie clearly has far more on his mind, and is more obsessed with aesthetics, like our own society. Hence the waxed and combed hair.
It seems reasonable that the Yeti has larger feet, thicker hair and bigger hands. But it is widely known that the Wookie is far larger in the penal department, and have an equally HUGE sexual appetite. Ging likes to think he knows all about Wookie manhood, so ask him any further questions on the matter.
Oh, and the Wookie eats meat and the Yeti is a vegetarian.
You can also use Yeti and Wookie oil, a build up of sweat and other miscellaneous debris, to create a potent aphrodisiac. 'Cos they're horny gits.