MauveCloud

CountVacula wrote:
Based on my understanding of HEPA (which admittedly is mostly from Wikipedia), I find it hard to believe that cloth bags could qualify as having HEPA filtration.  Could you explain that?

As far as the C-Vac replacement filter, I'd be willing to consider it if I wasn't already planning to replace the vacuum cleaner (though I'll wait another day or two to allow others to chime in with alternative suggestions), and I'm puzzled that only one store selling it shows up in Google Shopping when I search for the part number, while a total of 13 stores show up selling the Nilfisk-brand filter for $186-$404.

The $400 was not from the shop.  I called the manufacturer in December 2012 to get the part numbers and possibly prices.  I don't remember whether these are prices they gave me or prices I found, but here's the breakdown:
main filter (part number 61588200) $72.69
micro filter (part number 11730410) $36.92
hepa exhaust filter (part number 01727631) $225.97
vacuum hose (plastic) (part number 12041500) $76.01

Total $411.59

Your suggestion, the Panasonic MC-CG902, looks like a strong possibility, though I'm not finding any indication that it makes it easy to know when to change the bag and/or filters (since I won't always know how much the caregivers have used it).

I live with my parents in a luxury 2-bedroom apartment (1184 square feet).  The floor is mostly carpet, but the entry and kitchen have what I think is ceramic tile, with recessed grout, and the bathrooms and laundry room have what I think is linoleum style to look like tiles.

A couple of weeks ago, my mother's caregiver said the vacuum cleaner (a Nilfisk GS 90 that I think we bought in 1992 if not earlier) had stopped working.  I took it to a repair shop, and I was told that it was some voltage controls that had overheated because the bag was full (I don't know when it had last been changed, and the caregivers might not have known how to open it to check the bag; also, even before we started having caregivers come, I rarely thought to check the bag before using it).  He was having some trouble finding prices for them, but considering its age and that it was already overdue for more than $400 of replacement parts (the hose, the hepa exhaust filter, the micro filter, and the main filter), I figured it would make more sense to buy a new vacuum cleaner.

However, I'm having some trouble finding one that's a good compromise between the features I want and the cost.
Given that the failure was apparently caused by an overfilled bag, I figure I should get one that makes it easy to know when to empty the bag/bin, e.g. by having an indicator light turn on.
I'm fairly sure I want a canister vacuum rather than an upright (among other things, the space we used to store the Nilfisk in wouldn't fit an upright)
I want it to be reliable, and fewer/cheaper expected replacement parts would be good (e.g. bagless, washable filter).
A HEPA filter would be nice, since my father and I both have allergies, but probably not critical, since we'd continued using the Nilfisk even though it has been a little over 8 years (iirc) since last time the hepa filter was changed, so it probably had reduced effectiveness.

Can anybody suggest a vacuum cleaner that would be good for my family?  Preferably under $300.