I agree with you very much Nar, the cheap bagged vacuums with a filter in the bin are very very messy to emoty, and hair gets wrapped around those which is very dusty to remove. This is especially a problem with Vax bagless uprights such as the swift, and turboforce.
It had been years since I had a pure power, but as my Aunty, other Aunty and cousin own different types of Henry's, I can comment on the bags, and Hepa flos are used, they do have a nice rubber seal and a green tab which you push into the bag. Its a good vacuum and. I love it, but when. I take the bag off the black tube in the bucket, the dust can escape, but it's pretty easy to give the bucket a wipe or wash.
Regarding the cheap vacuum belts, that is very true, often they are not available in stores, and people dont have internet, and sometimes they are not available online which results in a useless machine