Peter: the side-emitters are also excellent for side visibility (as you'd expect). I used a red and a green one to make a prototype beacon (status) light for our CNC machines and they worked great. We currently (pun intended) use six red and six green 5mm LEDs arranged in a star configuration. With the Luxeons, the beacon light is much smaller diameter, shorter and about twice as bright. Unfortunately, the current light works fine and since the Luxeons come out to about the same cost, there's no reason to switch at this time except for the 'cool' factor.
However, it did raise awareness of high-power LEDs at the company and I now have a 5W Luxeon 'work light' in the prototype phase.
