I always really WANT to like bull pups, and then I shoot one and realize what a hot mess of ergonomics they are.
That's a neat setup, and I see they have one I could jam my P80 10mm frame in which might be interesting, but $500 is a lot for a range toy that I have to reload through my lymph nodes. I'd rather put that cash in my "parts for dual tube NV device" envelope.
If it were the $300 a Micro Roni is, I might be more tempted, although I realize that 16" barrel ain't cheap.