Usbrit, I have not tried the USP 1X, but it looks like a cool boat. I have rowed several Hudsons over the years and I can say that these boats have performed well, held up to heavy use and have a customer support that is excellent.
Paying about $13.5K US for a new boat seems a bit steep (I think it is in that range) although several manufacturer's have their top end 1xs in that price range. If money is no object, then why not, but I suspect it is.
I am sure you can find cheaper and or second hand 1Xs that have footstops you can modify for foot width quite easily. The convex seat rail is neat, but in my experience, as long as you keep the seat wheels and rails clean, the seat slides fine.
By and large, most 'innovations' these days are more marketing strategies rather than scientific and technical advances with verifiable speed advantages. If you are more comfortable or think a boat is faster, and can afford it, why not, though?