Other than the fact that it appeared to function flawlessly at a decent price (not a decent value in my mind) I quickly discovered a potentially serious problem.  It will only upgrade to MacOS Big Sur which Apple is ending all support for this December.  So if you choose to buy it using it online will be at your own risk.  If you are comfortable with this then it will most likely be a good value for you.I returned mine and bought a new "refurbished" one.