We are looking at the Zipper Wand, dual head walk behind wand. The reviews on their website (www.zipperwand.com) appear pretty good, and the videos of the tool in action are impressive. Anyone out there using it, and if you have had experience with it, what is your opinion? It is pretty pricey at around $2,500, but if it performs as well as it appears to, and lasts, the cost may be justified. They claim to be able to clean much faster, leave carpets drier, and have much less back pain than traditional wands. Your thoughts?