after gdr2, my battery life increased significantly. after installing gdr3, the battery has drained over 25% in 12 hours, before gdr3, I would get 2 days before I used up 25%,
running the developer preview, the battery life was the same as gdr2, so this issue is something Verizon caused after they got their hands on the software.
look at the attachment, that's my battery life after 12 hours running gdr2, now i'm at 75% after gdr3.
This morning, my phone battery strength dropped 10% in 3 hours, The Battery Pro+ app is estimating a 3% drop per hour. And SMS/MMS still randomly stops working. I have enable, then disable Airplane Mode to get messaging working again. Before the GDR3 update, I would get 2 days of normal use with the 8X. I don't see that happening now.
All - not entirely sure this will work with the HTCs, but. A friend of mine updated his Nokia Lumia 928 to GDR3 (developer) and he had the same problem initially. His power would drain to almost nothing in about 12 hours without even using the phone. This is what he did and it fixed the issue. Maybe this will work for you as well.
1) Uninstall ALL battery programs from your phone.
2) Use your phone and drain the battery completely until the phone shuts down on its own.
3) Use the corded charger (DO NOT USE WIRELESS CHARGER!) to charge you phone to 100%. If you can help it, try not to use the phone at all while it is charging.
4) Once phone is charged to 100%, reinstall your battery status program.
Nokia says this is called "reconditioning the battery" and it usually helps to "re-regulate" the discharging of the battery.
Also, remember that Windows Phone as a battery saving setting: (Settings - Battery Saver).
Hope this helps you guys with HTC phones!