I used to run a forge DV and it worked fine but didn't seem to operate as quick as the standard bosch unit, so i reverted to standard. The quality of the forge dv was excellent and cant see you having any trouble with them. Their aftermarket service is also very good and they'll even send you replacement pistons and seals when/if they fail - free!
The bosch (factory) doesn't need serviced but can fail. As said carry a spare, They only cost £18, so i can have almost 5 for the price of the piston ones and faster response.