Have the 991EX also, and yes it has some benefits if you are depending on muscle memory over a long period of time. But if you are a new user, or have multiple calculators that you go between, then this one is much more easier to get used to. Also there are many operations that are performed much faster on this one making up for the few more key presses you may have to do as compared to the 991EX. Most of all it has an Undo button. The font seems a lot more readable than its predecessor also. Though that is subjective.