I made up a GParted lve usb key with a SanDisk 2gb and will likely grab a 4gb for use as a 7 installer. Recently I made the mistake of grabbing a larger PNY 16gb when already having the same Kingston model.
The SanDisk was readily usable on a low powered usb hub while the PNY sadly wouldn't. Plus the PNY after a good reformat to clean off all of the factory goop offered less space then the Kingston when compared.
Out of the three however the main thing was not seeing as much need for power with the SanDIsk brand as seen with the others which can help avoid problems from the start.