I purchased this keyboard as a Christmas present for my wife, who is eager to learn the piano in her limited leisure time. It does a great job at this task, particularly when hooked up to her iPad in conjunction with Chordana and Synthesia. The lighted keys are a huge advantage to her as they show and wait for her to hit the correct note of the arranged song.
As a professional string player and intermediate piano player, I can say that it comes handy for some of my piano needs as well, such as computer notation and reading of piano accompaniments and scores for my string pieces. Its keys aren't weighted as a real piano, they are lighter and quite plastic, but I find them easy to play. The sound of its speakers is somewhat "plastic" as well, however you can instantly improve it if you plug the unit into a better set of speakers. You could also connect via USB MIDI to your computer and play better sounding banks via MIDI and through external speakers.
I fancy the 80's boombox handle in the back and the general portability of this unit. It is easy to carry around. You could even take it for a play in the park as it has battery power option!
I also like the harmonic and rhythmic accompaniments this gadget can do. We even tried the karaoke microphone input with my SM57. It works well, although there was some audible buzz into the speakers. Don't expect superior audio and midi quality at this price range. Otherwise it seems to be good value for the money it is worth.