Product review (3 stars): There are better options available.
In a pinch, these wicks will work.  However, don't expect the same performance as the stock wicks, nor the longevity.  When I first tried these, I was pleased, because they did work noticeably better than the stock ones once they've reached the end of their life.  We have hard water, and it's especially hard on these wicks.  For it to say "Extended Life" on the box, and to get the amount of use I was able to eke out of these (maybe a few good weeks total?), I can't really be overly positive about the product.  Unfortunately, these aren't even much cheaper than the Essick ones (when I went to the store to pick them up, they were rebranded as AIRCARE HDC12, but they mention Essick on the box).
I don't know if it's just the paper pattern used on these, or if it's the quality of the paper, but I felt like I had to replace these with the Essick ones just about right away to get much noticeable improvement in humidity in our home.  As I said, they do work, it's just not the level of functionality that I was expecting, given the "Extended Life" and other claims being made.  They're just OK, and if you don't need your humidifier to give you more than a little boost at times, maybe they'll work out for you, but in the Midwest in winter, we run our furnaces quite a bit, and we need all the humidity we can get.