The inserts have now been thoroughly tested. While I am not the best suspension tester around, I have a reasonable idea of what I like.
The front feels very planted on the road. It is firm, but still suck up what it needs to. However, I have not bought them for the road, I've bought them for stuff like this.
On very undulated tracks with cross ruts and the odd step, I was able to go pretty fast (well faster than I would have before). A few times I was caught out be unexpected holes or steps and was expecting trouble, but the suspension just dealt with it. Not once did it bottom out.
We went along some dry riverbeds with gravel that looked like sand. I was very happy the way the bike tracked and it was very stable at speed. Of course you still get the initial wobble while starting and stopping, but I don't think that's suspension related.
I have already forgotten how much I paid for the cartridges, but the grin on my face is still there.