From my knowledge, there's no current battery app that will give you a very "accurate" reading of your battery. All the battery apps out there will tell you exactly what the phone will say under settings -> status. It only shows by the 10%s. Therefore, you won't find an app that will say you've got 73% left or whatever. This MAY change once the phone is rooted.
I use battery status too cause I can click on the battery and it will give me a battery settings menu and quickly change things, or I can click on the % and it will display battery info plus other options. From the battery apps that I've tried, this is my favorite one. But I haven't tried every single one out there, just three of em.