Oh, and the difference in the heads you have posted is that one is much shorter than the other and will make up for the length of the loop. Look at how close the trigger is to the head of the release in the second picture. Of course Scott makes a regular release like this.
As far as wear on the release, I think it matters more on how well the release is made. I quality jaw type release should be just as good as a post type. Now a cheap caliper type with rough edges will wear a loop or string pretty fast.
This is the release I use now, It works very well right off the string. The jaw is large and rounded so it doesn't cause any serving or string wear.
Fletcher 3-D hunter
The picture sort of sucks though. I can take a picture of mine if you want.
If you were to get the Jim dandy release, get the claliper type, not the post type for the loop. That is what I have and it keeps coming off the loop. Other than that I like the release. However the other two I mentioned have much better triggers in my opinion. Truball makes some awsome releases, as does carter.
Paul