The Oreck Halo uses ultraviolet radiation to kill microbes in your carpet. I think it's a neat idea, but there are a couple things I want to point out.
1. UV radiation causes cancer. You wouldn't be exposed to it while vacuuming, but don't let your kids play around with it.
2. UV radiation can cause your carpet to fade. It depends on the carpet and duration of exposure.
3. I'm not paying $599.95 for a vacuum. It would be cheaper just to retrofit my old vacuum.