Just finished unboxing and testing. This is a professional level unit -- solid and study. Very well packaged, and all components are accounted for and in good shape (a few of the footbed medallions had shifted from their slots which is a simple shift and stick down).
Once I got the unit placed and set up, the test drive did not fail to impress. The 4D aspect is for real, and you can shift between each motor to suit your needs and preferences. I played with a few program options and tested a 10 minute manual 4D session at speed 25. I've been using a home dual motor machine (Axis Plate E6600) for the past 15 years (I use it every morning before stretching), and this Rumblex 4D truly does add another dimension. Time will tell as to durability, but initial impressions are that this is a very nice unit.
Reviewed large quantity of similar products and decided on Rumblexplus 4D because the 500 Lb max weight limit far exceeded all the others in this price range. Furthermore, Rumblexplus 4D uses 3 very quiet and powerful motors that offer the greatest assortment of movements that benefit rehab therapy, weight loss, and muscle tone. So far very satisfied with purchase!