I had these three and was able to compare the image quality:
I could not see any difference between the three of them. And they all flare banded if the sun was in the image. Some people claimed that this only happens with the cheap Russian Horizons, but nope, it also happened with my perfect condition Widelux F8 and Noblex.
In the end I sold the Widelux F8 because it was absolutely mint and worth a lot of $$ and I didn't want to put wear on it. It also, for me, was the absolute least fun camera to use with its limited shutter speed range, the VF blocked by the lens turret, and the terrible slim ergos.
The much fatter Horizon and Noblex are much easier and more comfortable to hold and use.
I bought the Widelux after being impressed by The Dude's website and his work with it. Just goes to show that something that may work well for someone may not work well for you.
I sold the Horizon because it had occasional random light leaks that would spoil what would have been really nice shots (judging those images), and even though it was in pristine condition the back door never actually latched closed! I assumed it was locked shut but could just open it w/o releasing the catch! When I examined it I found out that the build tolerances were so far off that the film catch hook could not latch onto the back door.
But this camera was by far the most fun to use. Fully mechanical with a great range of shutter speeds and by far the best VF. It's winning trick was being able to see the bubble level in the VF. A fantastic idea and I wish the others had that.
I kept the Noblex 150 Sport after I had it CLA'd (and rollers repaired) by Precision Camera Works' Bob Watkins. Same quality photos as the other two, but much cheaper with better features and easier to hold than the F8, w/o the light leaks of the Horizon. I stuck a bubble level on top of the VF housing so at least I could level it from waist view. I really really wish it had a level in the VF like the Horizon.
I really don't like the barrel in the middle distortion effect that these swing lens cameras give if there is a central subject close to the camera. It's like looking in a fun house mirror. But if your subject matter avoids that, then they are great.
I kinda do want an Xpan or TX Fuji because you shoot them like normal cameras. No need to worry about all the 'weird' stuff. But my perfect Noblex is $500, while the same Xpan/Fuji would be about $2000.
I'm almost tempted to roll the dice and get another Horizon U500/Perfekt and see if that one is better.