The Kepler is definitely a favorite of mine. The angled emitter adds such a timeless SW look to the saber, and its inherently light and sleek profile makes for good speed to your swing. I have both the silver and the black, and both are a must-have.
This emitter mostly works as advertised except that during a duel, the screw really comes loose with this emitter, and then it will start rattling and eventually slides off. I don't know if that's just how it is but I have not experienced this issue with other emitters.