rippling- none of those worries should be realized. usb monitors use DisplayLink technology, its a standardized format specifically designed to add monitors over usb connections. so theyre all basically the same. the -ONLY- downside right now is the lack of bios support- but i hear ati might be coming out with usb ports on their video cards just for displaylink monitors (that would be AWESOME)
the brightness is the same as any screen ive seen. LED technology has gotten good enough that you can get a lot of freakin light out of 1a of power. try staring at a 5w led flashlight, youll understand! ;)

