
I think there is a huge variation, depending on which vet does the surgery. A recent C-section by a vet that I hadn't used before, has left me with a toy breed that has only half its body hair. Okay, exaggerating a little, but I was gobsmacked to see her shaved from chest to vulva, and half way round her sides.
Have to have whoever is on call for out of hours obviously. Yet the vet that I normally use when I am able to actually book surgery, does the minimum in incisions. I did ask him about keyhole when I first heard about it. He was good enough to discuss in depth. And explain why he wasn't going down that route.
Certainly, there is a large outlay before this way can be used, and the vet said that the expense would be passed on to the client, and make a keyhole spay more expensive. He also said that using two incisions for keyhole would lead to a higher risk of infection, and, given that his incisions are so tiny anyway, he didn't see the point in changing. I do remember, after one particular spay, asking him how the hell he got a uterus out of an incision that tiny! His answer? Experience.
So I guess your best bet is to choose the right vet for the surgery.