We really like the quality of the PuRxium.  Alll the adjustments are easy to operate and the top panel well designed.  Our only wish is that the speeds would be more evenly separated.  Level 1 so low, we wonder how effectively it moves the air.  Our favorite and most often used is Level 2 which is very quiet and allows us to sleep.  However, Levels 3 and 4 are fairly loud making it difficult to be in the room.
That being said, we would buy this purifier again.