These can be bought directly at buydisplay.com by the way.
I have bought many 16x2 lcds from them and the service is stellar. Good documentation and flexible design. Most importantly they keep high level of compatibility in terms of controllers. Their lcds were the only ones which handled 4bit data line of Alesis Micron display.
In my view their black on white lcds are better than negative ones in terms of readibility and contrast.