I sell about 10 a year - roughly. They seem to do what the people want them to do.
Simple tub, only 6' 6" square, very quiet, very economical to operate - backed by HotSpring.
Note: HotSpring re-designed the Sumatran just a month or two ago. The changes were cosmetic only, the controls and other things had been updated just at the begning of the year. What I'm tryin' to say is: you may be able to get a floor model deal on one, if your dealer has one of the 'old' new spas!