I'm experiencing a significant improvment in battery performance over both the 9650 (Verizon) and the 9700 (AT&T). I receive approximately 250 emails a day and send about 25. I use the media player about an hour a day listening to music. I make or receive a handful of calls. And, I leave the WIFI option on and use it often during the day at various hot spots. At the end of the day, I still have upwards of 40% battery life. I couldn't even get through the day with my 9650.
I end the day at about 40-50%. With 9650 it was 20-30%. Seems like it's better to me with 340 software. I installed 340 when I got the phone so I don't know about previous releases.
I had worse battery life overseas with the 9650 and always changed to the extended battery. I'm going to try an igo external battery/charger this time and see how it works out. It will replace a charger in my bag and also be an external battery when needed. I just don't want to loose the thin feel of the phone.
