The battery is the same as the hero and tp2...
I have 4 spares for my Hero: 2 (generic 1500 mAh) I got from Ebay with the charger for 12 bux and the other 2 are the Mugen 1800 and Andida 2000 mAh. (Andida was also an ebay purchase)
The 1500's last as long as OEM, the others last a little longer, but not a huge amount.
Its well worth getting the spares if you are a heavy user like myself. Unless I am tethering I never plug mine in, I simply rotate batteries once a day. Something to keep in mind though is if you get a case, make sure its EASY to open if you plan to do like I do.
Its nice to have a spare with me (I got spoiled by that practice when I had my instinct) and not to ever worry about what the charge is on my phone.
Only downside was shipping took about 1-3 weeks for all them since they came from HK but everything came as advertised.
