If you were to look at the specs alone, the Samsung Galaxy Note 3 is actually still a very decent smartphone. With Samsung offering the pre-own models for only $250, it might be a better option than some of the mid-range and low-range smartphones in the market right now.
However, if you ever plan to get one, you might want to know that officially, you are only able to upgrade it to the Android 5.1.1 Lollipop which is nice but it is a few years old now.
The Samsung Galaxy Note 3 will not be getting the Marshmallow OS or the new Nougat OS but it is a small price to pay for what you will be getting in return. Since it is also an older smartphone that won’t cost much to own now, you can always root it on your own if you really want to try out the newer operating system.