do you have a favorite air purifier?

As long as I'm continuing to enter the office, I figured I should get some reassuring HEPA-filtered air to bring with me.  Today, I ordered this small portable unit because it was on sale since I last looked at it.

I need a new one for home use too, because my 25-year-old? filter that I have now is very very loud and doesn't work as well as in years past.  (Yes, I've changed the filter.)  So does anyone have favorites that they recommend?  I guess I'm looking for these qualities:

• HEPA (not "HEPA-like")
• a reusable pre-filter would be nice
• quiet
• good for up to 200 square feet (60 square meters)
• no ionic mumbo jumbo
• no ultraviolet stuff needed

What do you recommend?