Expansion Shield X300 is a one of the most cost-effective shield which could apply to Raspberry Pi Model B+ and Raspberry Pi 2 Model B. It integrates a lot of very useful functions such as RTC real time clock, audio input and output, USB hub, Bluletooth, WIFI, SATA interface. With this shield, you can build Raspberry Pi projects more easily and save both time and cost.
Compare with Expansion Shield X200. It adds some new features like SATA and BLuetooth, but it cancels HDMI and VGA video port. It is more suitable for project.