I used it once many years ago. I guess it worked, but it was a bit hard to deal with and a pain to clean out. I'd much rather go with the gfo.
The one thing I did seem to like was the small bottle of lube it comes with. I've used that with regular flax to help it seat and it actually worked pretty well for that!
I guess one try is not a thorough analysis, but I probably won't experiment with it again.