I have built the started shield and it works fine on the Arduino UNO Rev3.
Because I want to control a Servo when the alarm expires I need an extra PWM pin and a Timer to drive it. I bought an Arduino Mega2560 R3 so I can use Timer 5, Pin 46, 45 and 44 with the Servo library.
But when I use the standard sketch the clock is not working correctly. Only the Alarm time is displayed and the clocks stops blinking the colon. If I put the shield back on the UNO the clock runs fine again.
Can the shield be used with the Arduino Mega2560 R3?