I bought a Huck Norris after stuffing a Flow Mk3 and chucked it in last night (rear only). The foam itself is much harder and more dense than any camping, yoga mat or expansion joint foam I have handled and I can see it working well until it has been compromised by a decent hit. I think two or three strikes in the same spot and you are out.
I had a ride on it last night with the rear at about 24psi, which is about 3psi lower than I would usually run, and it felt interestingly different to running the same psi without the foam. You can kind of feel when the foam starts to squeeze between the tyre/rim and the tyre feels supple, yet well supported. I am yet to hit anything rocky or gnarly, but I did hit several decent roots at speed (Fall Line for those who know Red Hill) which would normally result in a bit of a bang at 27ish psi and felt nothing.
Considering it cost me around $225.00 to replace the last rim I think $60.00 for one strip, shipped, is well worth it if it only saves my rim one time. I actually now wish i bought a pair so I could run one in the front too.
YMMV, just sayin'.