I've got both. . . the 3AA seems to have a bit more throw, but also more "artifacts" like rings or darker spots. No surprise about the throw. The head of the 3AA is a bit larger, so I expect a bit more. . . but neither has a very far throw. The Jr. also seems to be whiter, though this may be due to the luck of the luxeon lottery. The main advantage of the Jr. is it's convenient size. . . it is essentially a MiniMagAA with a clickie switch on the tail, a vastly superior switching method, IMO. The 3AA also does NOT allow for momentary operation. . . the light turns on as you release the switch, i.e., on the "up" click. Since this is not how I typically use lights, it's a bummer for me. The Jr. is cheaper too. I would recommend that if you buy only one, get the Jr. Or do like everyone else on CPF. . . buy one (or more) of each!