A.F.
I have airborne allergies and I used to have a cat. So, when it came time to get a new vacuum I did a lot of research. It was important for me to have a vacuum that would last and have great suction. After doing research online, and visiting with a number of vacuum stores, here is my feedback.
-The power of the vacuum and suction of the vacuum are very important. There are lots of vacuums out there that simply are not very powerful.
-You want a "sealed" HEPA vacuum, as this also directly impacts its suction vs. non-sealed.
-I went with a midsize vacuum that was easy to maneuver and carry around. I have a basement and two floors, so it was important that it not be a big chore just to move it around.
-For that reason, I did not go with a dyson because I found it rather large
-There is a place in Evanston called AA Moley and they specialize in HEPA vacuums. You can give them a call and they will consult you over the phone.
-By the way, brands that are very good are Miele, Bosch, and Electrolux.
Good luck!