I tried the blocks when they first came out and had poor results with them. Unless they changed / improved, I'd stay with the Sims limb savers.

Oh, and that blue thang in my pic (above) is not attached to the bow... it's my Scott Mongoose release. I bought that back in 1995 to match a Hoyt Defiant Supreme I used to shoot the IBO. Liked the release so much I just kept it. The original wrist strap is long gone but the release still works as well as the day it came outta the box. Scott, makes real good stuff.