Just played more of Rock Band 3 with the new keyboard/keytar.
It really is ingenious how Harmonix ramps difficulty up from 'normal' mode easy through hard and 'pro' mode easy through hard. It is very easy to get started in normal mode, it's just one hand on five keys, very simple. And very easy to play standing up like a keytar. Pro mode requires both hands and you'll want it on your lap or on a table.
Like the drums, getting started in simple but will take a long time to master. And you definitely feel like your playing a piano and doing ok once chords kick in and octave shifts start happening at higher difficulties. You might even think you're getting quite good until you run into a great pianist's music like Elton John!!
Suddenly you feel like you just got taken to school. Which is really what makes music games like Rock band so exceptional. You learn to appreciate all the elements that go into making a great song, and which bands have stronger musicians on which instruments.