Likely something with the Q9M required a preset output. The droid does not require any exact mV rating. I think the chargers in question were made of crappy components with serious quality issues and nothing more. Hell, if someone sends me one I will run some tests on it.
Use what you like, but below are just a small few complaints over just the last few days about those chargers that "fit". Also search "Droid Charger Problems" and read until you fall asleep tonight. No matter what you think not all chargers and cables are made alike, just because they use a common connector doesn't make then a PROPER charger/cable. AND just because a worker in China slapped a spec label on it doesn't mean it passed quality control to verify its function and output. Of course if you think differently I know where you can get boatloads of sheets of drywall :-)
FWIW, I would trust a charger approved for the Droid from a company like Belkin.
Just a handful of post from the past few days.
You may be right that it isn't all that important, but personally... I am happy to err on the side of safety in this regard. I will stick with the Motorola chargers for now... at least until iGo comes out with a tip that is rated for the Droid.
still haven't gotten my phone in but I'm in a similar situation. My tom tom uses a micro usb charger and thus I have a car charger, in theory...
I'll have to double check and make sure its the right voltage though.