I recommend an electrolux canister vacuum, metal canister, made about 1976 (blue, gold, brown, before they went plastic.) Buy it at a flea market, then put a new motor in it. Here's my story:
I bought a house in 1981 with expensive, thick, wall to wall carpet. 25 years later we decided to put hardwood floors in to replace the worn out carpeting. The floor man tried to prepare us. "When we lift up this carpet, the foam padding will have desintegrated and we will have to shovel the dirt and padding out with shovels. This happens to everyone, dont get upset." And when they pulled back the carpet,there was no dirt, no desintegrated. They literally rolled up the carpet, rolled up the padding and carried it out. The flooring guy said, wow I've never seen this, you must be an amazing housekeeper. (Nah, I don't clean, I quilt ha ha). It is my vacuum that is amazing, I wouldn't live without my metal electrolux. (new motor cost $90.00)
Yes I had animals, yes I had pee spots.