We use the Honeywell Insight series portable HEPA air filters. I have several, in different sizes for our most occupied rooms. This is in addition to the HEPA system on our whole house system heating and air conditioning system. We considered several others, including the Austin Air, but came back to Honeywell for reliability, consistent performance, more compact footprint and ready availability of filters. Both of our kids have other types in their homes and have had to search high & low and wait for replacement filters at times.
We live summers in an urban area, winters in an agricultural area so both pollution and dust mitigation are important to us.
I think the bottom line is, are you comfortable with what you have? How do you mitigate dust and pollution when you are outdoors? If you are OK with no mask, or an N95 mask, the Honeywell is better than either. If you always wear an N99 Mask when not in the house, then Medical Grade air cleaning makes sense.
Sue