Product review (1 stars): Apparently filters nothing, save your money for bottled water or some other alternative
I second every single thing that the user named "Janis" from December 2009 wrote.  I too bought a TDS meter to test the water quality.  I too was completely shocked to find that two separate GE filters removed basically nothing (or if they did remove something, they also must have added something else to the water as well like carbon from the filter, because the TDS reading was hardly less than or the same as the tap water).

Be warned: these filters are not worth the money and very well might not be doing anything to your water!  They're certainly not worth the money!

If you're interested in the details, here's the long story.  My wife had been telling me for the past couple years that the water from my GE filters tastes horrible and WAY worse than the Nestle bottled water she likes to get.  I told her I thought it tastes fine and that I could taste a slight difference between the tap and the filtered water, and so the GE filters must be doing something right.  I assumed the Nestle water just tasted different than both the tap and filtered water because of their small amount of minerals they "add for taste."

I don't like being wrong, but I'll admit I don't think I've ever been this wrong about anything in my life (and I hope my wife doesn't read this review--just kidding!).  The water here in Arizona is admittedly miserably hard (around 700PPM average from my tap).  The World Health Organization recommends no higher than 600PPM and the EPA recommends no higher than 500PPM.  The filter that had been in my refrigerator for 6 months (and that I'd been drinking from that entire time) read around 650PPM before I replaced the filter.  The new filter I had purchased to replace the old one was apparently defective and came back about 750PPM (that means it was ADDING something to the already terrible and arguably unsafe 700PPM tap water--and this is AFTER filtering through about 5 gallons of water to make sure it was broken in properly)!!!

The seller was great and filled out the GE manufacturer warranty info for me and I had a new filter is just a couple days at no additional cost.  But this filter too was far short of my expectations.  After breaking it in again with 5 gallons through it, I have not yet gotten a reading below 650PPM.  Often it is in the upper 600's or even low 700's--which is basically at the normal tap water level or just below it by a statistically insignificant amount!  Now the GE filters do seem to help the taste slightly, and I don't have the ability to verify GE's claims about removing certain specific contaminants.  But even if it does get some things out, the overall level of TDS in the water is still higher than the generally considered safe limit, and so what's the point?

Here's the shocker: I had always heard news stories about how your bottled water might not be as safe and pure as you think.  Well, every single bottle that I have tested from the case of Nestle bottled water my wife drinks has come back between 45-75PPM.  No, that's not 450-750, that's literally not a single bottle over 100PPM!  Under 50PPM is considered ideal drinking water, and under 100PPM is still great.  Over 500PPM is dangerous for long-term consumption and if my untrained understanding is correct, it also apparently makes it harder for your body to even get some of the benefits of drinking water in the short term.

My recommendation if you're concerned about actual water quality rather than just taste is to avoid these GE filters like the plague.  Buy an HM Digital TDS water meter on Amazon here (I got a cheap one for around $15 and it works great).  Test out various types of bottled waters or other cheaper filters, and then pick something long term that you're comfortable with.

As much as I hate to use up tons of plastic water bottles, the health of my family comes first and since these GE filters are so expensive to begin with it probably won't cost me that much more to just drink bottled water instead.  We'll probably experiment with buying a large bottle of distilled water with a spigot and putting it in the fridge.  But one thing is for sure, after hundreds spent on previous GE filters over the past few years, that's the last $40 filter I bought.