Well I doubt you'll get any better pic quality out of a logitech one than an un-branded cam (Unless you but a £80+ logitech) , webcams were never designed for quality.
ALL webcams will do video to my knowledge, after all they're just a camera slapped into a USB port.
The thing you want to look for is the resolution and frame rate that the camera supports, these will be a maximum of 640x480 (which you will rarely, or never use) and 30fps.