While either should work fine for that book I would go with the Netduino Plus 2. In just glancing at the spec sheets a few things stand out.
Netduino Plus Specs: http://www.netduino....oplus/specs.htm
Netduino Plus 2 Spects: http://netduino.com/...plus2/specs.htm
Netduino Plus:
[font="Tahoma;font-size:small;"] ?[/font] [font="Tahoma;font-size:small;"]Speed: 48MHz, ARM7[/font] [font="Tahoma;font-size:small;"]
?[/font] [font="Tahoma;font-size:small;"]Code Storage: 64 KB[/font]
[font="Tahoma;font-size:x-small;"]without networking: 128 KB[/font] [font="Tahoma;font-size:small;"]
?[/font] [font="Tahoma;font-size:small;"]RAM: 42 KB
without networking: 60 KB[/font] digital i/o features
[font="Tahoma;font-size:small;"]
?[/font] all 20 digital and analog pins: GPIO [font="Tahoma;font-size:small;"]
?[/font][font="Tahoma;font-size:small;"]digital pins 0-1: UART 1 RX, TX[/font] [font="Tahoma;font-size:small;"]
?[/font] digital pins 2-3: UART 2 RX, TX [font="Tahoma;font-size:small;"]
?[/font] digital pins 5-6: PWM, PWM [font="Tahoma;font-size:small;"]
?[/font] digital pins 7-8: UART 2 RTS, CTS [font="Tahoma;font-size:small;"]
?[/font] digital pins 9-10: PWM, PWM [font="Tahoma;font-size:small;"]
?[/font] digital pins 11-13: SPI MOSI, MISO, SPCK [font="Tahoma;font-size:small;"]
?[/font] analog pins 4-5: I2C SDA, SCL
etduino Plus 2:
[font="Tahoma;font-size:small;"]?[/font] [font="Tahoma;font-size:small;"]Speed: 168MHz, Cortex-M4[/font] [font="Tahoma;font-size:small;"]
?[/font] [font="Tahoma;font-size:small;"]Code Storage: 384 KB[/font] [font="Tahoma;font-size:small;"]
?[/font] [font="Tahoma;font-size:small;"]RAM: 100+ KB[/font]
digital i/o features
[font="Tahoma;font-size:small;"]
?[/font] all 22 digital and analog pins: GPIO [font="Tahoma;font-size:small;"]
?[/font] [font="Tahoma;font-size:small;"]digital pins 0-1: UART 1 RX, TX[/font] [font="Tahoma;font-size:small;"]
?[/font] digital pins 2-3: UART 2 RX, TX/PWM [font="Tahoma;font-size:small;"]
?[/font] digital pins 5-6: PWM, PWM [font="Tahoma;font-size:small;"]
?[/font] digital pins 7-8: UART 3 RX, TX
(also works as UART 2 RTS, CTS) [font="Tahoma;font-size:small;"]
?[/font] digital pins 9-10: PWM, PWM [font="Tahoma;font-size:small;"]
?[/font] digital pins 11-13: PWM/MOSI, MISO, SPCK [font="Tahoma;font-size:small;"]
?[/font] digital pin SD/SC: SDA/SCL
(also works as UART 4 RX, TX)