I've not had good results from Mugen Power 1900 mAh battery. It shuts off when the battery percentage gets to 15 %. Thus, it's performance is worse than the OEM standard battery that comes with the phone.
On the other hand, I'm having good results with the Mugen Power 4000 mAh battery. Yes, it is big. But it's worth it, to me.
Tweaking settings might be your answer. Keep screen brightness to 30% or less. Turn your mobile data off with a widget during times of the day you know you don't need it. Those two things will elongate battery life more than anything.