Consumer reports rated the Hoover Fusion as not recommended due to emmisions, although it is true that the vacuum has good suction. The Hoover Mach3 and Mach5 are brand new and not reviewed by Consumer Reports at this time. Hopefully Hoover has fixed the emission problem. The Mach5 *does* have a HEPA filter, so hopefully that model filters better than the original Fusion and Fusion Plus!

Hoover Mach 3, Mach5 and Fusion are only available at Wal*Mart online or B&M (in stores).
Hoover Fusion Plus only available at Sam's Club online or B&M.
The Maytag Legacy is only available from Home Depot B&M.

More reviews.

Another site with a discussion (also mentions "the patent" issue).

The only 'care' which the Mach 5 will need is:

Remove the cyclone assembly from the clear bin once a week, turn it upside down, and remove the hair/fluff that clogs the exit from the tapered cyclone. This is important to do with ALL the Hoover cyclonic models: fusion/fusion plus/maytag legacy/mach 3/mach 4/mach 5/fusion 2.

Wash the pre-motor filter once each month, using water only, no soap, allow to dry.

Wash the post-motor Hepa filter once each year, using water only, no soap, allow to dry.

Change the drive belt once each year.

From Cycloneman:
The Bissell Healthy-Home is a copy of the multi-cyclone design of the Dyson DC07/DC14 series. That means it separates even more of the very fine dust from the airstream, keeping it away from the filters.

Bissell Volocity and Hoover Mach 5 are dual-cyclone models. They work just fine, but require somewhat more frequent cleaning of the pre-motor filter. Mach 5, in addition, has a tip cover on the end of the tapered cone, which has to be cleaned (takes just a moment) when the bin is emptied. Just pull the hair/fluff off the tip of the cone, and you're ready to go.

Eureka 4880 series came out about seven years ago. Instead of using two cyclones traveling at different speeds (as in Dyson and all other copies), Eureka's machine uses two cyclones spinning at the same speed. At the time 4880 was designed, Dyson's patents were still in force. Eureka 4880 passes a large amount of fine dust to the pre-motor filter (which IS washable). Which means you will spend more time cleaning the vacuum up than with other models. Also, the Eureka is VERY heavy.

My choice would be based upon several factors. IF you want to clean bare floors AND/OR want to use the attachments often, I would definately get a model with a brush shut-off switch. Bissell Total-Floors Volocity, or Hoover Mach 5. IF it's not that important, but carpet cleaning IS, I would recommend the Hoover Mach 3 or the Bissell Volocity. The only real difference is the brush shut-off switch.

Bissell Healthy-Home DOES indeed weigh more than all others, even a pound heavier than the already-heavy Eureka 4880.

I see nothing wrong with the Total Floors Volocity Bissell. IF you add a pre-motor electrostatic filter to the filter drawer, the Total Floors give you everything you would want in a cleaner - great suction, dual-cyclone filtration with NO tip to clean on the tapered cyclone, a very long hose, brush shut off switch, and a very well balanced machine. Also, since the Bissell uses an identical brush bar to the Hoover's, it should clean just as well.

My ONLY gripe about the Volocity (either the standard or the "Total Floors" model with brush shut-off switch) is that the upper cyclone stays in the machine when the dirt container (bin) is removed. This allows a small amount of fine dust to fall upon the body of the cleaner while the bin is removed. A small price to pay for a very good machine at a decent price. Oddly, the Bissell Volocity series (regular and total floors models) as well as the Power-Trak series have an odd smell for the first few uses. It's a combination of the plastic used to make the cleaner and the smell of the Hepa filter. One of the ingredients of ABS (the plastic used to make vacs) is "Benzene" (the "B" in ABS) and in some cases it can have an odor, especially as it gets warm (hot) when a vacuum is used for a while. This smell passes with a few uses, but it IS noticeable for a short while. Hoover and Dyson machines, which also use ABS (but from a different supplier) have no odor.

Multi-cyclonic "should" refer to the fact that there are more than ONE tapered, high efficiency cyclone. In ALL U.S. Dysons, the Dirt Devil Spinnergy, the Bissell Healthy-Home, and the Shark Infinity - they use 'true' multi-cyclonic technology (developed by Dyson). It means that these machines have the maximum amount of airflow, and the maximum amount of separation with regard to fine dust.

Dual-Cyclone units use the "original" Dyson technology (developed in 1983). There is only one high efficiency cyclone (tapered) and one 'low efficiency' cyclone (the walls of the clear bin).
Dual-cyclone technology is still light years ahead of a pleated filter in the bin (like in all other bagless machines).

ONLY the Hoover series (Fusion/Fusion Plus/Maytag Legacy/Mach 3/Mach 4/Mach 5) does the tip of the tapered cone need frequent cleaning. But even at that, it takes no more than 5 seconds to pull the hair/fluff from the tip of the cone.

The Eureka 4880 series does NOT use true dual-cyclonic technology since there is NO tapered high efficiency cyclone. As such, the Eureka does not suffer from dirt collecting at the tip of the tapered cone. However, the Eureka *does* suffer from a pre-motor filter that is forced to take a large amount of the fine dust, reducing suction and causing frequent cleaning of the pre-motor filter.

Interestingly, the Hoover, Bissell, and Dirt Devil models all use virtually identical brush bars. Since Dirt Devil and Hoover are now the same company, and both brands are made in the same factory (in China) by the same people, and the same engineers work on developing both brands, the cleaning ability of the Dirt Devil Spinnergy and the Hoover Fusion/Mach series as well as the Bissell Volocity series, is about the same. It's really only the convenience features (hose length, brush shut off switch, thickness of plastic parts) that differ. Of the three (Hoover, Dirt Devil, Bissell), while it's true the Dirt Devil uses more 'advanced' multi-cyclonic technology, the Dirt Devil does NOT work significantly better than the Hoover or Bissell versions to recommend it OVER the Hoover or Bissell.

Each purchaser should ask themselves the question "how important is the brush shut off switch to me" before deciding on one of them.

With Regard to Dyson Models:
The DC07 offers the most Bang for the Buck. It's a true multi-cyclonic machine and has lifetime filters. DC14 cleans no better and is NOT a better value than DC07. DC15 "the ball" is heavy and awkward to use, cleans no better than DC07 or DC14, and is not the best value for the buck. DC17 has an extremely aggressive brush bar, which means it *can* remove more carpet nap than the softer DC07/DC14/DC15 brush roller (a concern for anyone with expensive, high pile, thick plush carpets).