I upgraded to the new EVO from the original HTC EVO 4G launched in June of 2010. That phone was excellent with great speeds, large screen, and a kickstand. The one thing that was common but almost accepted by many was the relative short battery life. This is if you did use your phone with any meaningful amount throughout the day you would need to charge it or battery swap at some point to make it. But let's say you didn't really use it too much, you didn't stream music/radio on your unlimited Sprint plan or download videos or talk all day. Well, I'd bet you had a spare battery or a charger with you at all times, no? but your mileage may vary with other large screened android devices for sure.
How about the new EVO? To say it's been an improvement well, doesn't do it justice.
I know I'm comparing it to a now 2 year old device, but many "OG EVO" users are upgrading to "The new EVO". This is all I have to compare it to. This is how it stacks up for me thus far. I get email all day long, I make and receive phone calls off and on but not to a large degree as I average 1,400 minutes each month. I do browse the web and use apps that access the internet. I do not tether anymore without any "4G" available as of yet, hard to justify the $30 add-on. I have no live wallpaper, LTE turned off, I use WiFi quite often, screen brightness on auto, Best Wi-Fi performance UNCHECKED, I use no screen lock or timeout just manual button. I do have GPS on, weather updating every hour, weather animations with sound, update my location in real time, there may be other settings I'm missing at the moment.
Friday 2:35pm --> Sunday 5:00pm
50 hrs 25 min
So this is what I've experienced with my first week and a half of ownership. Day one screen set to brightest and playing with it all day I got 11 hrs. Since then I've got at least 17hrs+ battery life starting early morning of a weekday experimenting with settings. The results illustrated above represents light usage on 2nd day still far far greater than the "OG EVO" could ever hope to achieve. With the phone being out since May 24th there are pages and pages of EVO 4G LTE threads on AC. Many on there are now reporting 18-48hrs of battery life. The overnight battery usage is literally 0 or extremely close to it.
How will it do with an LTE network to connect to? Well a growing number of people are connecting to it, but not enough yet to report experiences this early in launch of device and network.
As far as the EVO 4G LTE having a non removable battery, any concerns I had prior have all been erased. This is not just due to the far greater than expected battery life. It's also knowing that with at most half the number of charges or "cycles" this internal battery will see should significantly extend it's performance and life cycle vs the old removable battery on the "OG EVO".
As to why the big jump in battery life, maybe it's the new Krait chipset or ICS or the combo I dunno but I love it.