I don't know if technologies have changed much in order to change this calculus meaningfully since I last checked, but here's why I like berkey filters:

    1. Although filters are expensive upfront, they last a very long time and are cost-effective as a result
    2. The large containers keep clean water accessible and at hand for things like cooking, and not just drinking
    3. The simple design makes it so, were something to go wrong, I could craft my own filters onto their plumbing once the filters are spent. A ceramic filter would be trivial to make, for example.
    4. Their filters last a long time so I don't need to frequently buy disposable filters and generate more waste. The waste from their filters is also minimal and predominantly biodegradable.
    5. The system is low tech. It'll clean rain water in a pinch with no electricity. I don't need anything special to keep it working.
    6. If the filters slow down, I can clean them to get them working better again. This makes them very versatile for off grid use where the inputs into the system might not be as clean as city water. This would ruin a lot of filters on the market.
    7. The aesthetic gains!