I've bought a Rainbow vaccum cleaner a year ago, but there are a lot of other brands we can choose. One of a German brand is also very good. You are advised to get some more info and have comparison before you invest almost 20,000 for a vaccum cleaner, though you can pay by installment of 12 to 24 months term . On site demonstration is available for such kind of vaccum cleaner.
As I've been confirmed by the salesman that Rainbow is not totally filter free. There is a filter that you may need to change annually or bi-annually.
In addition, after sales service is just on request basis.