Mosquito Bite for sure.
I've used it extensively alongside Polystar Energy, and MB wins in almost every category: tension maintenance by far, better feel, better control.
In terms of power and comfort, they are very close, but while Energy turns into a rocket launcher over time, Mosquito Bite is a longevity string which doesn't become uncontrollable in the any way like PE; MB maintains just the right balance of power/control/feel for longer than any poly I've tried (all this is with gut mains setup in a dense 18x20 midplus... see sig).
Head Pro Tour 280/630. Tour Bite 18/Mosquito Bite. Sampras serve, Agassi backhand and Federer forehand. heh heh