Yeah they all seem great the first time you vacuum, but then no matter how clean is the filter they just don't suck. I don't have $70-$100 every month to go and buy new one especially knowing that it's not gonna pick up what it's supposed to. I don't have pets and the carpet is short. Is there anything else out there that works? Does Dyson work as they claim? Please don't tell me to switch to wood floor or tile.
I own a Kirby. My mother owned a Kirby. I have a neighbor who owned a Kirby for twenty years. She just bought a new one. She didn't retire the old one which still works, but put it in the garage to vacuum the car. (with attachments, of course, not as an upright.) We live in high dust country, the arid southwest. A Kirby is high end on the purchase, but it can vacuum up what the wind brings in for years without problems. Even if it ever has problems, a small engine repair shop can probably refurbish it for you. Just be sure to order lots of bags, and change the bags out regularly.
We use Dyson animal. it works great.
We have a Royal upright. We have 3 dogs and a cat inside. The Royal picks up all the hair from the carpeting. Change the bag frequently.
I have a Dyson, it is very good with good suction but it will cost you around $599 but is worth paying a bit more for in the long run. I have had two cheap vacuum cleaners and both were hopeless. Hope this helps