I am a vacuum freak. I just have always been interested in them. When I was little l loved the feeling of superiority I felt when I rolled that vac along capturing everything in it's path!
I have owned many vacs and would advise you to stay away from oreck. The magnesium is their response to all the complaints regarding their standard vacs. Our church has one and I tell you it is a pain to use...literally. Any vac without height adjustment is poor engineering. Just say no.
One of my favorites is the Eio from Germany, but they have not been sold here in the USA for a while and it would be difficult to get any support for them.
I can recommend the Riccar enthusiastically. It is built in the same factory as Simplicity, and their vacs have a very good and well deserved reputation as well.
Miele's are great but they are German. When they work they are superior, but they can be somewhat difficult to work on. It reminds me of German engineering during WWII. The Tiger I tank was basically a rolling pillbox with a very sophisticated anti-aircraft gun for it's main weapon. I think it needed maintenance performed on the gun after 25-30 shots because of the tight tolerances. The US and Russian tanks could literally have dirt in the barrel and fire shells all day long.
The Miele has some of the best filtration you can get.
Another German vac that I like and seems to be built a little more robustly than the Miele is called Sebo. They also have an excellent reputation.
Mind you these are serious vacs and you will be paying several hundred more than something at Costco. I don't think any of the vacs I have mentioned will let you down.
I actually think Dysons work pretty well but they are designed to work for about 3-4 years.