The Playground Sessions Piano Learning System ( from $159 with keyboard) is an app-based tool for learning to play. Co-developed with the legend, Quincy Jones, the set comes with a five octave keyboard that connects to a computer or tablet (not included). The link means that the apps can tell if you're playing the right notes at the right time. The system can work with PC, Mac or iOS systems.
The Playground Sessions Piano Learning System is the second app-based learn-to-play system I've looked at in recent years, the first being the ONE Smart Piano Keyboard with lighted Keys ($213). Though there is superficial similarity there are significant differences. In my opinion, the Playground offers a more polished curriculum. Lessons have a "shape": concepts are discussed, and then put into practice in sub-lessons. This is a bit more like the traditional experience of working with a music teacher who guides seamlessly as you level up. From the introductions with cameos from Harry Connick Jr. to the selection of melodies (like I Want To Hold Your Hand) it seems targeted to an older crowd. On the other hand, the ONE system includes Guitar Hero like games that may encourage the video-game raised generations to keep practicing.
There are a couple of other notable differences. The ONE system uses Bluetooth to connect to a smart device. The Playground, at least on the hardware I tested, uses a USB cable, included. However, if you intend to use it with an iPad you'll need a USB to Thunderbolt Adapter, a hidden cost and surprise that could mean not being able to use the system on Christmas morning when the stores are closed.
Also, the ONE system has keys that light up as they are needed. To me, this was a nice feature, particularly for those just learning how the staff matches up to the keyboard. This is particularly true for senior users who may have trouble reading the small musical staffs on an iPad.
As mentioned, on balance, I give the edge to the Playground Sessions Piano Learning System because it offers a more coherent pedagogical approach.
One last thought: if your child is also taking music lessons I would consult with the music teacher before investing in either. The teacher may find that the lessons run contrary to the way he or she wants the child to learn.