Pros: energy efficient, fast
Cons: loud(if unbalanced), adds extra step to laundry
The concept of the spin dryer makes sense. It's basically like a powerful second spin cycle. You can pull 2-3(or more) cups of water out of your damp clothes from the washer in a few minutes with this device. That's water that your heated dryer doesn't have to work hard to evaporate. Additionally you are getting any residual detergent and any minerals that may be dissolved in your water out of your clothes instead of baking them on, good news for people with lots of black clothes.
The spin dryer is smaller than I had anticipated, only 2.5 feet high. You can't fit a full load of laundry into it (unless it's a small load, like the one I had for the video (below, if it works)), generally you'll have to break the load up and spin a couple of times. That's not a big deal because it's pretty fast. It's not quite as fast as advertised (2-3 minutes) more like 5-6 minutes, still not a big deal. It also depends on how dry you want your clothes to be. Since I want to get the majority of the water out of my clothes with the spin dryer I went longer, until the stream of water coming out of the nozzle had really tapered off.
It can be pretty loud, as you'll see in the video. However, that is because I had the load unbalanced in the spin dryer, I've done a few loads where it was balanced and it didn't get nearly so loud. So be sure to try to make sure that there is no extra spaces between the clothes when you're loading the thing.
Finally, the clothes come out quite dry, not totally dry but very dry. Actually some of the clothes come out completely dry, depending on the material. The few towels I ran through it came out no wetter than if you had just used the towel to dry yourself off from a shower. You could easily hang them to dry and they'd dry out fairly quickly. After spinning the clothes I put them in the normal dryer for 15-20 minutes. Our dryer has a cool down cycle that starts when there is 10 minutes to go so if I start it then the heavier stuff like jeans don't get totally dry. Finally, this thing takes A LOT of water out of your clothes. I had started with a 16 oz. cool whip container to catch the water but that proved too small and upgraded to a larger tupperware.
That said here's the video, it's not all that great but you can kind of see how it works. Sorry the lighting in my basement sucks.
The draw backs are obvious, you're adding another step to your laundry, so it's not especially convenient. You also have to fold your damp clothes and be careful when you're loading the spin dryer otherwise your load will be unbalanced and the spin dryer will be really loud when you run it.
On the other hand, all the water you remove with the spin dryer is water your regular dryer doesn't have to dry, which means that's gas or electricity you're not using. Additionally this reduces your drying time significantly. You can dry a load in about the same amount of time it takes to wash a load, so you'll get done with your laundry sooner.
Overall I like the spin dryer a lot and recommend it to anyone who isn't lazy (or who's desire to save money (or energy) is stronger than their laziness).