We are previous owners of the x400 Dreammaker hot tub.  We had eleven years of  fairly reliable service with this tub and were very satisfied with it.  It was the reason we chose to replace the old tub with the Ar400 tub.  We couldn't believe the purchase price Wayfair
offered for this unit.  We paid $2399 in 2005 for the X400, and paid $1850 appx for this one.  It has been refined in the eleven years
that they have been making them.  This one uses a common inexpensive filter and the filtration is slightly different from our original
one.  It has led lighting and the cover is the highest quality.  We are thrilled with our new tub and use it twice a day.  It also seems 
quieter than our old tub.