This is Miele's ad copy of the S4 ...they said it better then I can.

S4 Galaxy Series
World Premiere...Of an Out of This World, New Vacuum Cleaner:The S4 Galaxy Series.

Lightweight, Powerful andStylish...One Giant Leap for Vacuuming.
The well-appointed S4 Galaxy Series is light in weight and has everything an advanced vacuum cleaner should offer and more. With out of this world cleaning performance, an advanced HEPA filtration system to protect your indoor air and the enduring quality and durability that have become international staples of the Miele brand, you will certainly appreciate the ingenuity born from the many details endowed in S4.Why not explore the excitement and the difference a Miele S4 vacuum cleaner can make in your home?

Breathe Easy, With a Little Help From Miele
For almost 80 years, our research, development and quality control laboratories have tested methods to effectively pick up and, most importantly, retain dust and other indoor air pollutants. After collecting volumes of data, engineers and designers continue to reach the firm conclusion that Miele’s system is the most effective and hygienic method of removing particulate matter from the home. Our exclusive combination of a Sealed System™, using the very best raw materials, electrostatically charged IntensiveClean Plus™ dust/filter bag and a selection of high-quality filter cartridges, including a certified HEPA filter, provide the essential formula for this success. As a matter of fact, the S4 Galaxy series has been awarded certification by the DMT Air Quality Testing Institute, an independent institute that monitors air hygiene. The S4 joins other Miele vacuums — which were the world’s first to receive this certificate — with a top rating of “excellent air quality”.1 This certification refers to Miele’s HEPA filter and the vacuum cleaner working together as a Sealed System™ to provide maximum protection for indoor air quality.Please exercise caution when evaluating other vacuum filtration systems, as there are many gimmicks that do not work as effectively or scientifically. As this is an area where the results can be devastating to young or elderly lungs, or to anyone who suffers from allergies or asthma, please visit Integrity Vacuum a local authorized Miele dealer to discuss the importance of the indoor air quality in your home and how a Miele vacuum cleaner can improve it.

An Out of This World Vacuum Cleaner: The S4 Galaxy Series
Quality. Quality. Quality.Miele’s maxim, for everything!S4 vacuum cleaners are manufactured at Miele’s Bielefeld factory in Germany where every effort is made to embrace the company’s 107-year motto of Immer Besser or Forever Better. Endurance testing in custom-built laboratories form an intrinsic part of quality assurance on all Miele vacuum cleaners. Before any production process begins, all components are put through rigorous tests and subjected to enormous strain… stress that exceeds typical residential householduse. Only when all components, electronics and floor tools have successfully passed each critical exam will the Miele brand name be bestowed on them.The Longevity TestMiele vacuum cleaners are tested to last a minimum of 1,000 operating hours or an average of 20 years residential use. This is only possible because of the critical Miele-made component of the vacuum cleaner… its motor. The S4 features a high-output, Miele-made Vortex Motor System™ that is capable of consistently providing top performance for over 1,000 hours of use.The Cable-pull TestA malfunctioning cable reel assembly is frustrating. That is why Miele cable reels are put through a very aggressive quality assurance exam. The cable is pulled out and retracted over 10,000 times as a part of Miele’s approval process. With this assurance, you can be sure your cord reel will function reliably and safely for years.

The Floor TestMiele floor tools and accessory cleaning brushes are inspected just as thoroughly as the vacuums themselves. They are tested on miles and miles of different flooring, and must tolerate a fall test, in which the floor tools drop from a height of nearly three feet over and over again. Only when the floor tools endure and pass this test, are they approved for production.The Threshold TestQuality assurance engineers at Miele’s factory test the daily challenges of the vacuum’s castors, bumper strip and outside casing using a volume of different tests. For example, on the threshold exam, the vacuum endures miles of track where typical and not so typical stresses are exerted — simulated door thresholds, bumps and harsh curves — in order to put maximum strain on the vacuum.The Hose TestMiele vacuum hoses are among the best in the world! Each production lot is subjected to countless bend and stretch tests in our laboratories. To test the endurance of the hose, a vacuum cleaner, plus an additional 5 kg weight, (that’s over 11 pounds) is stretched thousands of times. The hose must pass undamaged before being approved for inclusion in a Miele vacuum cleaner box.