I don't think I ever heard about Berkey filter before.

I have use a water ionizer from a company called jupiter ionizer. I have a discontinued model called melody.

The water that come out is day and night from unfiltered water. Everyone needs a water filter unless sometimes when people's water come from a very pure spring water.

http://www.jupiterionizers.com/AlkaViva-Melody-II--Open-Box-Special_p_194.html