The DRV8801 is a better choice (it's the one we use on our Rugged Motor Driver
. The MAX4427 is a MOSFET driver, not a motor driver, which means it's not intended for sustained "high current" loads, just the instantaneous peak loads of driving MOSFET gates. Furthermore, the MAX4427 output resistance can be as high as 12 ohms at only 10mA, while the DRV8801 is less than 1 ohm, meaning you will lose a lot less power.
50mA unloaded means it could go quite a bit higher with load -- I don't think the MAX4427 is giving you all that much headroom. But, since it's a DIP package and is relatively inexpensive, it might just be worth trying out. If it smokes, time to move up!
Note that the TC4427 is essentially equivalent and quite a bit cheaper.
The Gadget Shield
: accelerometer, RGB LED, IR transmit/receive, speaker, microphone, light sensor, potentiometer, pushbuttons