i have the following lights: 2009 MaxxD, 2009 Joystick and a new 2012 Diablo. i have also owned several NiteRider models and a Light and Motion Stella. i dig the cable free design which has been exposures claim to fame.
i have to say that the new Diablo is pretty damn close to the perfect light. if i had to choose between my Diablo and my MaxxD i'd choose the Diablo. even on medium it is wicked bright but on high its amazing. the only improvement needed is a 2h burn time on high... also, i dont know what the numbers are but the Diablo on medium is brighter than the Joystick on high. its really a stellar light with a very slick design.
i think exposure lights are close to being too expensive and having to buy an extra mount can set you back some coin, but man the Diablo is one sweet light. cant recommend it enough.