I think this is a pretty decent deal, so grabbed one myself. I currently have the Stage 4 model in my bedroom, but wanted another for our living space. These are great for allergies and also very quiet.
This model is the Stage 5, which also has a pet filter layer. It has decent reviews on Choice and elsewhere. The cheapest I have ever seen is $440 earlier on in the year (Amazon) but this deal comes with a $45 gift card and an extra set of GT filters, which are valued at $289, so it's better than the Amazon deal.
What is a GT filter?