I've noticed Noblex prices dropping on eBay, I assume due to the popularity of pano heads and stitching software, but I think a real swing lens camera produces a better result.
I was shooting 6x17 for a few years before getting the Noblex. Lacking a 5x7" enlarger, I just didn't have a great way of dealing with the 6x17 negs, though they made nice contact prints, and seeing the sharpness of the Noblex negs really convinced me. Some subjects work better with the swing lens projection, and some with the flat projection. If I really need the flat projection, I just shoot another format and crop, or if I plan for it, I've got the 7x17" camera.