As the other reviewers have said, this is a great keyboard for the beginner or the person who just wants to play around. If you are looking for a professional keyboard, this is not for you.
I recently decided to learn piano and bought this keyboard as a good starter keyboard (instead of paying thousands of dollars for a real piano). I was pleasantly surprised. The sound quality is excellent. The speakers won't blast you out but they are strong enough. Also, the instrument sounds are very realistic for an electronic keyboard. The grand piano sound sounds more like a piano than the old upright I practice on at a friend's house.
The number and variety of the sounds, beats, and songs is good. The play-along feature is great! You choose a style (with drums and bass). You can then intro into the song. There are always two different tempos to switch between with short breaks to transition from one tempo to another. So at the push of a button, you have a backing band for whatever you want to play. This was nice as I am practicing basic jazz improvisation and it is good to have a backing beat to work with.
The keys and displays are set up intuitively and after about 15-30 minutes of playing around, you'll know where everything is and what you need to do.
The keys are well spaced and have a touch sensitivity that works well.
I have not tried the more advanced features on the keyboard, but the manual appears to be well written and helpful.