I have one on my Summit. I only hunt out of my climber 1 or 2 times per season, but its great for me. Much easier to deal with than the Summit seat. Easier to pack, lighter, and only a little less comfortable.
I've never heard of those...just looked it up. I made one of those for my summit probably 5 years ago. I took the grocery net out of the trunk of a car and tied it together with paracord. It looks like the same thing.
I don't use the Summit very often anymore. As I've aged I just feel a little safer up in a ladder stand.
Still, I have the Hazmore net seat but prefer the Summit. More comfortable and sits a little lower in the frame (I typically get in the stand early and will often take a nap. I feel like sitting a little lower in the frame is safer).
Summit seat is like a Lazy Boy as well - it's very comfortable).