We have a Brita pitcher, and had a ZeroWater pitcher in the past. In terms of real world usage, the Brita filter cartridges are about half the price, and last about four times as long. We replace our Brita filter cartridge every few months with one member of the household drinking out of it regularly, plus guests. I still drink straight tap water myself, because it's easierand I think it tastes better.
Get the smaller pitcher or else it takes up too much room in the fridge.
It still feels ridiculous to be buying those filters, but as they say: happy wife, happy life (or happy spouse, happy house). And still beats the hell out of the insanity of buying bottled water.