@ddljohn-- As far as I know, application and result wise, there is no difference between the two. The only differences are that bovine collagen is more affordable than human collage. And human collagen is hypoallergenic whereas bovine collagen has a risk of causing allergic reactions.
If you ask for my personal opinion, I would go for bovine collagen. Doctors are required to do allergic testing before they use bovine collagen anyway. So you will always know beforehand if you are allergic and the doctor won't continue with the treatment if you are.
So the question comes down to cost. Both of these will eventually get broken down in skin and disappear. And since most people get these injections on a regular basis, it's better to get the more affordable one which is bovine collagen.