I have a Kirby Diamond G series, one of my favorite Kirbys as it has two speeds. We have mostly wood on the main level, room-sized rug in living room and smaller rugs in other rooms. The low speed on the Kirby is one of the best features for odd jobs like these. Although the dog doesn't shed, he brings in lots of dust (severe drought/dustbowl here this year) so there is lots of fine dust, etc. and the Kirby with a filtrete material bag is fine for the small amount of vacuuming it is required for. I gave mom a Kirby G many years ago and she loves the Tech-Drive; plug it in, back it out of the closet and drive it back in when done.
I have several other vacs *small collection to choose from including a Miele Earth w/powerhead and a Tri-Star canister w/ 10' hose. Both of these are wonderful cleaners for hard floors, above floor cleaning, etc. I tossed out all of the Kirby attachments save the hose, most of those tools are silly and/or weak performers. I found another $49 Diamond G at a Goodwill a few months ago that for some strange reason I was compelled to bring home, but left behind the tools & caddy. I haven't seen Kirby at Costco, could this be one of the "special event" sales they have periodically like those crappy, overpriced pillows?
In the cleaning biz, we use backpack vacuums, straight suction. Excellent performers in all settings, we had a country club account for 17 years and never a complaint about carpets not being clean. Larger items, of course, had to be picked up before vacuuming, club staff was pretty good about resetting rooms before leaving them for cleaning crew. We supplemented the backpack with a variety of uprights, but they saw little use as it took triple the time to clean the same space a backpack could do. Edges, stairs, hard surface floors and hard to reach areas were always cleaner with the flexibility of the backpack. ProTeam makes some of the best, but I've had good service from some of the no-name units as well. It helps being able to work on them myself - most have common problems that are easily repaired, switches, power cord pigtails, etc.