I've had the Everpure system at my kitchen sink since 1986, it also feeds the icemaker. Works great! Use it for our drinking water as well as for making coffee and tea.
I change the filter once a year at about $80, ordered on line.
I think most plumbing supply places, and appliance showrooms sell the unit, as well as replacement filters.

I have had Everpure filters from the mid 1990s. I started out with a h300 and now have a h1200. I replace filters twice a year but I use filtered water for the ice maker, hot pot and cooking. We also drink a lot of water as a household of 3. I would not buy a refurbished filter as I don't know what that could mean. The filter columns are built in a specific way and the everpure column is pretty hard to break apart. I purchase replacement filters from Amazon and a few other reputable sources online. The price does not vary much but I take advantage of any discounts on websites when available.
What filter faucet are you getting? I have the Waterstone cold and hot water filter and love it so far. I had a mountain plumbing filter faucet before but was not very impressed with the quality. When it gave up the ghost, I purchased a waterstone.
Good luck!

We have it in conjunction with the everpure polaira. The water tastes great and the filter doesn't take much room under the sink. Our plumber wanted to wring my neck but was able to fit a disposal, lines for two dishwasher, the chiller and filter in our sink base cabinet. The chiller one of my favorite parts of our new home. I purchased from superwater.com and found their pricing on the chiller much lower than anywhere else. Haven't shopped the filters around yet as I haven't replaced it yet. I'd use that site again without hesitation, though. Good luck!