Product review (4 stars): It works! But you really have to force it
I had the same problem as many reviewers had: the filter didn't work at all with the o-ring in, or else it leaked a huge amount.  What worked for me was to put the filter in (with label and notch in front), then to twist it to the right very hard, despite sprays of water and alarming noises coming from the fridge. The O-ring is probably a little too thick, so you have to use the extra force to squash it down so you can turn the filter all the way.  Otherwise, the water seems sweet enough, the flow rate is fine, and the price is much more reasonable than the GE filters.  Hope this lasts longer than the GE filters, which usually are good for about 3 weeks in our fridge before the water flow gets ridiculously slow.

Edit 1.5 months later:
The filter is still going strong.  People, if you are having trouble installing this thing, give it one more shot. Try twisting it another quarter turn, use both hands and a lot of strength.