As Trevor says you need to think long and hard before going down the Noblex, Horizon route because of the curved film plane. I considered buying one but need more accurate rendition of landscape & buildings.
My Gaoersi 6x17 is quite practical to hand hold, but then where I live the light is nearly always good and that makes a huge difference. Personally I prefer the extra quality of using 120 compared to 35mm so never really thought about an Xpan.
Again: I own a Widelux now and like it - just want something with a flat-film-plane setup.
Film size is a consideration, for sure. But loading up any kind of film means for me, by definition, taking a bit more time and being more careful. Whichever format, I'd use slower film and a tripod when going anywhere near 1/30th.
I may even sell my F7 and some other gear to get a new pano system - any hints on a ballpark price (apologies if this is veering off topic)
I've just bought a secondhand Fotoman 612. You get 6 images per 120 roll film. Mine came with a 65mm Caltar lens. I am pretty amazed at the lack of distortion at the edges of the frame.
I have a couple of test images here:
They aren't technically brilliant, they were my first two images taken with the camera, and they are compressed for the web. The prints on A3+ paper are stunning (in quality at least).
I used an X-pan for a few years and always got superb images if lab processed, but never could get great scans from the negatives (Epson 4990).
Easier and better scanning of the 6x12 negatives was my decision to go to the Fotoman.
Oh, and although the Fotoman is bigger and heavier, it is built like a tank, no batteries or electronics, and I can use my LF lenses when I get the appropriate cones.