The price-performance ratio is measured on the expensive Britta Maxtra filters outstanding. The filter performance in lime is much better. We have an extremely hard, hard water here. With a 2-person household of Britta Maxtra are on after 5-7 days, and it shows up again in the lime kettle. The PearlCo creates 10-14 days as a single filter. If you, however, is used 2 containers with 2 filters and run a use filters of about 10 days already used as a prefilter for the vessel with a new filter, the term is extended, amazingly, almost one month. The tightness in the hollow of a vessel Britta is very good, removing the spent filter works by the two recessed grips at PearlCo easier. When Britta tears you up because the plastic ring. We have completely converted to PearlCo UNIMAX and filters now half-price Maxtra.