iBatt2: I had the earlier version of this on my old G3 500 iBook, and it helped me track issues with two aging batteries. It's $19 shareware, but does offer more than the other apps. iBatt2 offers multiple windows, some of which supply the same data as the freeware apps, such as current charge capacity versus the original capacity. A second window supplies the serial number and manufacture date of the battery, as well as "average time to full" data if you're charging and "average time to empty" data if you're on battery power. A third window uses data from other users stored online to compare your Mac laptop's battery to others using the same model. In addition to the raw capacity numbers, iBatt2 assigns your laptop battery a grade. My MacBook's battery earned only a "C." The software also charts your battery's power activities on a graph that updates itself automatically. Finally, iBatt2 has some cool-looking but not terribly useful gauges at the bottom of the screen showing wattage and charge levels.