This is the board that I learned how to control GwtS/MwM devices and learn Arduino in general so it's near and dear to my heart. My original is limping along from abuse but I'm still using it for development. I picked it up from Radioshack for ~$20 but you can find them cheaper online. These work perfectly for recording and transmitting at the same time while debugging thanks to onboard USB and a separate UART. While some people don't like the ATMega32u4 chips because of certain little bugs, I've learned how to work around them and the features outweigh the pains.