A Google search led me to this thread as I was trying to see what I could sell my monoski for. After reading the posts and being reminded how awesome these things are, I decided to keep it. I'm an older guy (45), have been skiing since I was 10 years old. In my 20's I decided to give monoskiing a try and loved in. Kept at it for 15 years before going back to skiing so I could teach my kids (I would never recommend monoskiing unless you are already a good skier).
Contrary to the belief of some in this thread. Monoskiing doesn't create bad skiing habits. If anything, it improves your skiing. I cannot tell you how good your balance gets when you cannot pull your feet apart to catch yourself. Monoskiing forces you to use more "angulation" (not sure if that is a real term, just what I use) in your hips/legs. This is directly transferable to skis. I was a good skier prior and could ski just about anything, but after being on a monoski for all those years, it only got better when I went back. And the idea that you are all screwed up because you've been on a different edge- well that is ridiculous. There is no adjustment process when back on two boards, it is automatic.
The only places that skis excel at (imo, of course) are on ice, occasionally a traverse, going uphill in deeper snow, or potentially getting yourself out of a tricky spot that you didn't intend to get into (oh sh** this cliff is bigger than I thought). I've had my share of sketchy moments as I got in a potentially bad situation. But that happens no matter what your a using to get down a hill. Also be prepared to get an upper body workout as you have to push yourself around more with your poles as you can't simply walk or skate from point A to B. These are easily overlooked once you realize how great they are in powder and bumps. And my favorite, in tight trees with buried tree stumps launching you into each turn.
One thing I didn't see mentioned is that when in very deep snow (waist high or so), you can better control your altitude. You can do what I call "dolphin turns" where you use your tip to control your depth to pop out of the snow to make a turn. You don't need to do this of course, but it is very fun. Also, and this was important for me, since I used to spend my time in the Lake Tahoe hills... A monoski could care less if that deep snow is wet and heavy sierra cement. It is just as effortless as dry powder.
So now I have a question for those on monoskis. Where the heck can I get my old board re-mounted with new bindings around here? I now live in the Portland area.