I am not a fan of these "block" style targets. I had one of the originals, when they first came out, and my first shot sent an arrow buried up to the fletch in it. After that it didn't take long to be completely shooting through it. Then I got a great deal on a barely shot Block 4x4 that didn't even last half of the 3D season. It was an insert robber too. Truthfully I've not found any of them to hold up long with even field tips...and I know shooting with broadheads would only double or triple the attrition rate on them.
My next target, in which I will be buying here in a week or so, will be a Morrell Range bag. The ones I've seen at the local 3D shoots have been there for 2-3 years and took many thousands of hits, have been out in the weather the whole time, and still look good and are stopping arrows.