I never could get the claw type to work very well. By the time you get it in the slack on the claws pulls the nuts inside so close together there was little compression. Awkward as could be. And the shifting issue was always there, gets tight and they slip on the spring (at least the ones here, somewhat glossy powder coating on the spring). Even with some old inner tube glued to the tips of the hooks, still slipped.
I bought the internal with the two plates, it worked fine.
I made one like the WCCC one, found it a huge hassle as it compresses the spring, then what? You pretty much have to pull the UCA, and then unwind the tool as its bolted to the shock tower cap, to get the spring off the tool. With the two plate one you can remove the spring only, and reinstall without removing the perch or UCA, a big plus in my view. Especially on the big blocks, very little access to remove the UCA nuts unless you pull the engine...