Allow me to go off on a tangent here and give my history with vacuum cleaners. My mother had 3 vacuums that I recall, one was a Kirby upright which I was scared to death of--a big, evil-looking, growly thing with bright eyes. The other two were canister vacuums which are still functioning today (I am putting that in bold because this is my main point!!). I'm sure the Kirby is still running also, but my mom got rid of it because it was too heavy.
My first vacuum was an Electrolux canister. I decided I hated canisters because I was forever knocking things over with the hose. I'm busy watching the floor where I'm vacuuming, but the hose is off doing it's own thing, knocking things off shelves and tables, leaving a trail of destruction behind me. Additionally, the canister--devious thing that it was--would come charging at my heels like a bull. It also liked to hide around corners and door jambs and refuse to follow me into the next room. Very temperamental.

Needless to say, it took a while to get used to the "self-propelled" feature and my furniture is a bit worse for the experience. It was like the thing had a mind of its own-- "No! I am going THIS way! Don't try to make me go THAT way."--and the thing would just take off and ram my coffee table!
In the first year the sensor thingy that turns off the brush roller when the vacuum is parked upright broke. That was probably due to the thing tipping over every time I used the hose, but that WindTunnel kept going (with issues) for about 10 years.
About two summers ago, I gave up on the WindTunnel bought a new Eureka upright. Let me just say, this thing is a piece of junk! I've had issues with the brush roller since day one; it's extremely difficult to turn it on and off. And it is not self-propelled and is quite difficult to maneuver, especially on stairs. Though I am small, I'm no wimp, I have a 40 lb toddler I carry around! The only nice thing I have to say about it is that it doesn't tip over when you use the hose (probably because it's so dang heavy).
Recently, the brush roller has started goofing off--"I'm off, no, I'm on, no wait, I'm off again." Smoke comes out and stinks up my whole house. My toddler got upset and thought the house was on fire the last time I used the vacuum! I changed the belt, thinking it had become loose and it broke within 10 minutes.
I have come full circle and am now back to canisters. I was thinking about getting one anyhow since we have a good mix of carpet and hardwood floors at our new house. Sears had their Progressive on sale this week and Consumer Reports gave it their "Best Buy" blessing, so I bought it.
I took it for a test run yesterday and love it! And I can vacuum the stairs without endangering my life or the lives of those standing near the stairs! I still have issues with the hose getting into stuff and the canister having periodic fits of being uncoorperative, but if this vacuum can manage to stay operative for more than a couple of years I will be happy. (Isn't that pathetic--I've certainly lowered my expectations now!)
So, to answer the question, "Is cleanliness next to godliness?" my answer is no, not if you're cussing up one side and down the other at the blankety-blank vacuum cleaner!