It's longer at 44.9 mm but narrower at 13.8 mm. The size isn't an accident actually. It was designed so that it would closely match the dimensions of an AA battery.

PWM pins work the same way across all Arduino boards, so you don't need to go out of your way to buy a Mega if you already have a board supporting PWM. On the Uno, Nano, and Mini, the PWM pins are ...

Meanwhile, the Arduino Mega is getting the same USB chip along with an ATMega2560 processor with twice the memory. Right now only 128K is available, but that's a software limitation and they're ...