Altera and Xilinx are the big-boys in the FPGA world. They duke it out by offering more complexity, bigger parts, and more features. Often times, these extra features are overwhelming, especially to beginners. The datasheets on the high-end parts are thousands of pages! If you're trying to learn Verilog or VHDL, that can be very intimidating.
On the other hand, the Lattice ICE40 FPGA that is used on the Go Board is much simpler. The tools to generate the FPGA images are slimmed down, to let you focus on what's really important: learning to write FPGA code. If you're looking to get started as easily and quickly as possible, this Lattice ICE40 FPGA is the clear choice.