To the original poster...my advice would be to buy the Miele S2 Delphi, for a few reasons: It is made in Germany and uses the 1200W Miele Vortex motor (the same as all other current Miele vacuums). It uses the larger G/N bags, which hold quite a bit more compared to the FJM of the S4. WHen you have pets, that makes a difference. Finally, it comes with an electrified hose with pistol grip, on/off switch for the power nozzle, a telescoping electrified wand, and the SEB 217 nozzle. This is a small and quiet nozzle, and while it does have soft bristles, combined with the Miele suction it wants for nothing in regards to pet hair pickup...it's very effective. It also has a squeegee-type strip behind the brushes that catches everything...it's a very effective hard-floor nozzle. The 217 is so light and quiet (and gentle) that I often connect it directly to the handle and use it for stairs or the couch. At $499.00 in the US, it's an incredible deal, unbeatable in my opinion. If you opt for spending $99 more, you can get the red Titan which adds a bare floor tool and a HEPA filter...the Delphi uses the clean air filter that comes with each box of bags, and is quite effective in my opinion. It's also upgradeable to the HEPA. I don't work for Miele, but I do have an S4 and an S2, and the S2 is a better machine in every way (bigger bag capacity, power nozzle). I hope that maybe helps you in some way.
There is no comparison between the S4 and S2 comparing build quality and Sealed system. The S4 is a VERY well built, solid machine with a totally sealed system. I hope the new replacement for the S4 will have the same quality as the present S4 and not the S2.