Originally Posted by elcreative
It isn't the voltage (which is, as you say, 5v), it's the CURRENT and the real difference is quality/speed of charge due to available current... USB sockets on computers supply a maximum of 500mA (and often less) whereas wall chargers normally range from 1,000 - 2,000 mA which means that the charge time is substantially reduced as well as never stopping (and discharging the device) by going to sleep... they give optimum charging cycles as battery is are designed to take fast (high current) charging to 80% and then drop back to trickle charging to finish. This probably does extend a single charge cycle if you read the manufacturer and inventor's specifications for Li-On and Li-polymer batteries and is certainly more efficient as well as taking less time to charge.
Yes more amps may charge the device faster if the device can handle it but that isn't necessarily a good thing for the battery and is also very unlikely to make the battery hold more.
Looking at my Sony Vita charger it supplies 1500ma and looks like it's pretty much the same charger Sony uses for the T1 so I'll presume the T1 can handle it.
Convenient and potentially faster to charge I'll agree but holding more charge I still have a problem with, while stranger thing's have happened I still believe the slower a battery is charged the more effective it is.