These two work great as a pair and I'm very happy with both.
The shield needed a slight mod to work with the Mega2560 because its serial jumpers allowed to select either pins 7 and 8 ('SwSerial') or pins 1 and 2 ('HwSerial'). Neither choice is particularly suitable for the Mega which can't do SwSerial on pin 7 and 8, and pins 1 and 2 are better left dedicated to the serial to USB. My answer was to remove the serial jumpers altogether and just patch the centre pins over to UART1 on the Mega (pins 18 and 19).
Note also that this board will not boot successfully unless either it or the host Arduino are connected to an external power supply. Powering via the USB port does… Read more
bought from this seller bundled with a GSM shield - arrived fast, brilliant little board and does everything I need. Loads of I/O and the 4096 of SRAM and 256K of flash is ideal for the fairly complex sketches I'm developnig at the moment :-)