I have only 1 1/2 experiences -- bad. Several years ago I bought a MagInnovision MXP17F new and liked it so much that when Mag offered a refurbished MXP17F at a significant reduction in price, I bought one for a second computer. It had serious color problems -- badly purplish splotched lower right screen etc. A replacement had the tray controls broken. The second replacement was fine. I will say this for Mag though, they paid for the shipping both ways to straighten out the problem. When the original MXP17F developed a problem under warranty, it was replaced with a refurbished monitor which also had to be replaced. The replacement I still have on an old backup system. So I have had three bad refurbished monitors, but ended up with two good ones. I can only say good things about the customer service at Mag, but not much good to say about whoever does the refurbishing for them.
Based on this modest amount of experience, I would never voluntarily buy a refurbished monitor. You have no choice if that is what you get under a warranty replacement.