Hiya skibler,
"I am not cleaning a mansion. I am not rich . . ." Welcome to the club.
As you have a relatively good rapport with the folks where you bought the Vibrance, take it back and tell them the truth. As for power nozzles, if you have no pets, kids or heavy traffic you may get along well enough without one if you carpeting is medioum to low height. Personally, "be prepared" being the motto, I like having a canister vac with a power nozzle even if I don't have a lot carpeting to concern myself with.
Keeping expense in mind, Miele bags and filters are kind of pricey and you should be prepared for that should you invest in a model from that brand. I own two. I don't believe that the Miele Olympus accommodate an electric power nozzle at all. (Forget investing in the air turbine version. It's not worth the money. ) It is my understanding that the Delphi, also in the S2 series does. If you can take the Riccar back, I'd suggest making an offer of $375.00 for the Miele Delphi with power nozzle and see where it gets you. Miele does have decent bags size, usually quiet operation and long warranties.
Though mine came with a bare floor tool along with the PN, I bought a straight suction carpet and bare floor combi tool for my Miele and use it quite often. I have to say I am rather pleased with its performance and it serves me well. Again, I have no kids, no beasts and am single.
Riccar makes a mid-size and compact canister which I have not used. Check out the pricing on those too plus the cost of bags and filters.
Not meaning to forget -- whatever you buy be sure there's convenient and effective speed/suction adjustment if you're feeling more "pull" than you'd like.
Still keeping budget and overall worth in mind, my next thought is that you might try looking at all-metal rebuilt Electrolux canisters. They clean decently and have a pretty good track record as regards endurance. I've spent my share of time working around the house with a good used vac and had as much success as I've had with brand new. The issue is sometimes not so much the machine but the care it's given.
Best of luck and lets us know what you decide on.
Venson