It's been ten years since this thread was started. I would think by now, he has made his decision!Agreed. Wynn Environmental is a great choice! If you're needing a replacement cartridge for Wynn, there is an aftermarket filtration supplier that manufactures them and other nanofiber cartridges.
Also, glad you brought up microns because they are an important factor in selection the right dust collector for you.
I would go ahead and give Harbor Freight a shot to see if there's a difference. It can't hurt to try it out.