UV, ionizer, etc. don't make sense unless a person has major concerns, and they expose people to other problems to consider too.
HEPA appliances are sufficient for many folks, folks like me who deal with allergies to just about everything.
Of course, now HEPA filter replacements are like the printer toner catridge situation: the appliances are priced OK but the manufacturers milk their $$$ off the filters.
P.S. and I refuse to go back to Dyson-like bagless so pay the filter fees
