It turns out I had a bad filter with my first ZeroWater pitcher, the company replaced it and the water was better and lasted longer (about 3 weeks with heavy use).
That being said I thought I would do a few comparisons between the ZeroWater and the Clear2O pitcher. First off the ZeroWater has a much more sophisticated filter with 5 stages and the Clear2O is a single stage with solid charcoal filtering. Don't confuse this with other charcoal filter pitchers as none are solid, they use powdered charcoal and that does not do nearly as good of a job. To get water through a solid charcoal filter you must have water pressure not just gravity feed.
So which of these is better? Well that is up for debate but the bottom line is, if you are filtering your municipal water it is already considered 'safe' to drink. So why filter? Simply for taste and smell, as well as the unlikely but possible contaminates in the water.
They use chlorine to kill off bacteria and other nasty critters in our municipal water system, and it works pretty well but sometimes things get into the water after most of the chlorine has done it's job. A filter that stops these bacteria and other health hazards is just a good idea.
The main problem with water treated with chlorine is it tastes bad. Well both of these filter pitchers will make the water taste good as they get rid of the chlorine equally well. Both will get rid of most strains of germs and bacteria, at least the most common ones found in water supplies.
The ZeroWater can get rid of some nasty chemicals that the Clear2O cannot but municipal water supplies are tested for these chemicals several times a day so in reality this should not be an issue unless you get your water from a well or other un- monitored ground source.
So for healthy water I feel that both pitchers will do the job and both fix the taste and smell equally. However there are some differences in their use that make one stand out.
First the ZeroWater unit is a gravity fed unit, meaning you put water into a top reservoir and gravity pulls it down through the filter. Problem here is that this is a slow process and since the top reservoir has less than half the capacity of the bottom one (the drinkable water one) this means to get a full pitcher you need to fill it, wait, fill it again then wait then top it off a little. I found this to be the biggest drawback of this pitcher.
The Clear2O has a unique filling system unlike any other filter pitcher I have seen to date. It has a hose on it that attaches to your faucet with a quick connect fitting that then uses your water pressure to force the water through the solid charcoal filter. This is more in line with the way larger installed filter systems work, basically you can have a full pitcher of ready to drink water in under a minute.
The ZeroWater comes with a testing unit to see if the filter is still good. The Clear2O has an indicator window on the pitcher itself to tell you when it needs a new filter. Green means you have up to 40 gallons left, yellow 10 gallons and red when it's time to change the filter.
While the ZeroWater tester should be more accurate I found it showed time to change way too early, and the taste of the water is what I used to tell me when it needed to be changed.
Both units have easy to change filters but the 5 stage ZeroWater filters do cost more due to their complex 5 stage process. Both should in theory give you about the same amount of good drinking water (if you ignore the meter and go by taste).
One feature the ZeroWater unit has over the Clear2O is it has a spigot on the bottom so you can fill a glass without lifting the unit out of the fridge. But the overall size and weight of the Clear2O pitcher is smaller so it's easier (and quicker) to take it out and pour a glass.
End result, if you are on municipal water and drink a lot of water I recommend the Clear2O unit. If however you have certain health risks (auto immune) or are on ground water you might be better off with the ZeroWater unit just as a safeguard against other contaminates that the Clear2O won't take care of.