I am a bit late to the discussion about the Leather Refinish, but I wanted to add my opinion.
For vintage bags I admire the "vintage" part, I like to make them look better not like new again. Clean, condition and touch ups on the corners, clean brass, etc... is as much as I am comfortable doing it.
For new bags, it depends how much I like the bag and how much damage to it. I made a mess of a white crossbody using the acrylic paint and moisturizer, I should have used the LR instead, but I didn't know about it at the time. I have used it and I am very happy with the results on the corners and straps of a Parker. I had to mix shades to get close to the color (magenta and cream), not perfect as it was my first use of it, but I am happy. I used their Leather Refinish solution as well.