The Coonan 357 was out of production for a couple of decades (+/-), and has recently been reborn. They are a slightly modified 1911 design (linkless barrel, external extractor, pivoting trigger), but due to dimensional changes, I'd consider this a proprietary design.
You will not get the benefit of being able to use parts from a variety of manufacturers [except maybe the hammer/sear/disconnector], so you are at risk if a relatively new vendor goes belly up or stops production. One of the beautiful thing about relatively "pure" 1911 and AR15 designs is that you can buy a unit from an upstart vendor and know you will still be able to get replacement parts even if that manufacturer disappears. So, there is some risk this will become a "curiosity" in future years (sort of like the Bren 10).
The grip is obviously rather long front to back, which may or may not be to your liking. I've seen them in the old days, and the new ones at the Shot Show looked pretty much the same.