Just a thougt about recharging.
With regular (AA, etc) batteries, you can get fast chargers which recharge quicker by providing the batteries with more milliamps. The downside (apparently) is they might not last as long during use, and over time may suffer with a lowered capacity.
With that in mind: by intentionally charging over USB (500mA), instead of using the mains charger (1000mA), would the battery eventually develop a slightly higher capacity?
It'd probably be something you'd have the measure with software in controlled tests to see any difference...