This question is so easy. A water distiller only can distill 1 gallon water in 4 to 6 hours. Therefore, if you need plenty of water to drink, cook and wash, a distiller is not your best choice. I haven't use a Big berkey filter filter. However, I think a RO filter is much better, because it also can remove chlorine, fluoride and as well as other contaminants. If you are looking for the best reverse osmosis system, this link may help you.