We've got 2 Hunters. It was a package deal from Sam's Club so they were inexpensive...around $150 for both. You have to keep an eye on room size when you buy these things. We have a small house, but could use a couple more. I have no clue if it's really doing anything. It must be doing a little bit 'cuz the filters are gross already and we haven't had them long.
As far as I know, the HEPA filter is supposed to be better than a washable permanent type filter. But it's something you could look into.