The Fusion is a relatively recent innovation, and I wouldn't be surprised if some or all of the concept was protected by patent.
I have had a Fusion for 3 1/2 years, and I about 90% love it. The concept works -- having the large inside bag gives you excellent mobility, and having the Lycra skin on the outside keeps the suit from ballooning and gives you really good streamlining, for a dry suit. I have been amazed at the durability of the Lycra. After about 450 or so dives on my suit, the piping on the front is coming apart, and I have a run in the Lycra where I put the P-valve in. Otherwise, it looks faded, but intact, and it still works fine.
I love the fact that you can turn the suit easily inside out for cleaning and drying. I love the lightness of it, and one result of that is that I now dive dry EVERYWHERE, even in the tropics, because the suit isn't any harder to pack than my 5 mil wetsuit.
I did not and do not like the fact that you can't really put pockets on the Sport skin (I use X-shorts, which work perfectly, so long as one doesn't forget to put them on). And I couldn't find any footgear option that worked for me, so I put Turbosoles on the suit. (The current semi-attached boots weren't available yet when I did that, so I don't know if I would have liked them.)
Overall, of the three dry suits I've owned (laminate, compressed neo and Fusion) I like the Fusion the best.