No smartphone has good battery life, because you are asking the phone to do a lot with the limited size battery that's in the HD2.
Think about it, on every smartphone out there people have complained about battery life.
But if you are going to run a huge backlit display, play media, surf the Net, and make phone calls, you will be lucky with any smartphone to get more than about 15 hours use, and even with that, at 15 hours your battery meter will be near zero.
Poor battery life is a hardware issue, not software (unless you use aggressive battery management such as keeping your display at 10% brightness, having it turn off after a minute of non-use, etc.).
So the ROM is not going to give you better battery life, unless there was a defect in the ROM's power saving features, which on the HD2 that's not an issue.
Want great battery life, use a non-smartphone.
