Over time, they've steadily increased the webcam's sensor resolutions to deliver even sharper detail. They've even added a Ultra-HD model with an 8 megapixel camera that offers astonishing high definition resolutions up to 3264 x 2448 pixels. By adding a direct HDMI video connection in other models, connectivity options become more flexible. They can be hooked up directly to a display or projector. Using USB, they function as a fully Mac compatible web camera.
Models with WiFi support allow greater flexibility in doc cam placement. That can be useful when, say, a teacher wants to roam from desk to desk or worktable with the doc cam to highlight student work in progress.
IPEVO's document cameras have historically been good about conforming to the UVC webcam specification to assure easy Mac OSX level compatibility -- without requiring any additional web camera software to be installed.