So I found that you are hard pressed to get a full 12", it is more like 11-7/8" due to the pads. Perhaps after some use the pads will compress a bit and let you get the full 12". The other thing that I didn't see in the specification was what is the minimum space needed to fit the clamp in to use it as a spreader. That would be a nominal 3".
The pads have to be swapped around to go from compression to expansion, well that is if you plan to use them. In my cold garage they are quite stiff and not all that fun to get off and only slightly better installing. I would think that during the warmer times this would not be such an issue so if I want to be doing the swapping I think bring the clamps in and letting them warm up in the winter would be a good idea. The knob is very easy to change from clamping to expansion but you still have the pads to deal with.
I like the easy of use of the clamp except for the pads, perhaps the warm summer weather is more to their liking. The clamping force seems reasonable and clamp can be handled with one hand. Having the shorter clamp area on the back side might be useful for some projects, I didn't really play with that yet.
Long term use is still a question, while I had these all of about 10 days and only played with them a couple of times over those days I can not say how well they will do in the long term. I can say so far so good.