The Sphinx is an excellent "flashbulb" design. Anything my group uses an all-energy load-out 'Mech for, the Sphinx has a place.
The Sphinx 2 is a new favorite for special hunter-killer teams designated and equipped to hunt down advanced Special Forces stealth 'Mechs. In our campaigns, these units are a serious headache to any player team. Exterminators, Spectors, and Werewolves are the most common. But in recent times, the Raptor II and Stealth-5X have begun to make a name for themselves. We even have home-brewed Spec-Ops versions of the Chameleon and Morpheus using these systems. Normally, the HK 'Mechs assigned are all-energy weapons assault and heavy designs, since these targets are deadly in capability and pilots among the hyper-elite. The Sphinx 2 fits the bill to a tee, with it's targeting computer and MASC system as an added bonus to it's capabilities.
Just my two cents worth.