For video, the Nikon D3100 is the better choice of these two if you don’t already have lenses tying you to Canon. Based on the answers, its 1080p/24 fps recording is preferable to the 500D’s 1080p/20 fps, and it also offers autofocus in video.

The 20 fps vs 24 fps difference does matter. For static shots like a talking head, 20 fps may be acceptable, but once you pan the camera or film motion, 20 fps can look noticeably less smooth and more jerky. 24 fps is the more standard cinematic frame rate and generally gives better-looking motion.

If you’re open to another Canon body, one answer suggests stepping up to the Canon 550D, which adds 24 fps and is considered a much stronger video option than the 500D.