^this!!
I was planning to mod my BTU, but after using it in light painting a castle I decided to keep it as stock. It's a great "brush" for light painting large objects which are far away.
But I still want to mod it with some de-domed high bin XM-L2s on copper.. So buying another starts to sound good. But then again, having two stock BTUs would be even better for some light painting situations -> do I really need three of them? ;)