tbm,
I have some pretty sharp negs from my widelux, and I have in many cases handheld the images. But I mostly shoot medium format and the prints are certainly a bit softer than with my RB. I agree in some ways with rml who says that he thinks panoramics are a temporary fad. I disagree in that they have been around for many years and have been seriously used for many years with spectacular results. But I agree in that it is a very different way of seeing and most people probably don't stick with it long enough to really find their own vision with it. I had the camera for a few years before I figured out how to make images I liked.
Most of my panoramic images haven't been scanned and posted anywhere yet, but I do have one that is online Dead Link Removed. It makes a very nice print at 10" length, but is somewhat soft printed at 20" length. If you are aiming at large prints, a medium format or large format panoramic solution would be better. If you expect to print more at the smaller sizes, it is a great way to go.
The image in question was handheld at 1/15. I shot a whole roll of that one image to make sure one of them would come out. I also have shot at 1/125 and 1/250 handheld and have little trouble. At the angle of view this camera provides, 1/125 is very fast and quite sufficient for handholding. For 1/125 and 1/250 it is just a question of lens resolving power and subject distance (and proper exposure), but shouldn't be a real problem in terms of camera shake.
I have found that life is easier with a tripod, but the camera is easy enough to use that sometimes you can get nice images handheld even at the slow shutter speed. I have also found that when I find an image that works with the panoramic format, it works better than similar images taken with standard dimensions.
At the cost of these specialty cameras I can definitely see Ted and rml's point about renting before buying. But I suspect that if I hadn't picked up my widelux for $200 when the opportunity arose, I would never have taken enough pictures to decide I liked it. It was just a novelty for the first four years I owned it.
For Samuel B, I have heard about problems with the wideluxes, but haven't really read up to see whether I am familiar with any. I've worried about mine a few times, like the two times blowing pumice got stuck in the camera during an exposure and made the lens stop swinging and I thought I was destroying the gears trying to make it work again in the field. But both times it kept on ticking after...at least so far. I also have noticed that sometimes the shutter speed dial doesn't easily move all the way into a new shutter speed, and the camera doesn't like to make an exposure with the dial not quite resting on one of the shutter speeds. And last, I've noticed that the camera occasionally will have irregular swings when grit of smaller dimensions gets in the gears...which can make for surprise negatives.
As I said, I like it partly because I'm used to its idiosyncrasies. I would never have become so interested in it if I hadn't bought it and used it when the opportunity offered itself. I also would never have bought it for the price that they usually go for.
I think David's summary of the price difference is an important consideration if you are just checking out the format but want to give yourself more time to try than just renting would provide. If I were checking out the format and didn't get a great deal on one of the expensive options, I would probabaly also err on the side of a cheap Horizon to see whether the format works for me, and get a more robust camera later if it grows on me. And for all I know they might be better than a widelux. I happen to fall into the group that tends not to spend much time worrying about the possible advantages of the cameras I don't own, I'd much rather make use of the ones I do have...and I have a widelux...which I really love...
Good luck and happy panoramics!