Well, it is interesting because, I guess like many people, I use my phone (fairly heavy hands on usage) and when I come home plug it in to charge.
The biggest savings WMLonglife yields is when the phone is not in use and is not plugged in.
As an example, last night I made sure I did not plug the phone in. During roughly 12 hrs of no usage the battery dropped just under 15%. Normally, this would be around 30%. So, yes, the band switching and the data disconnect do make a difference but not if you are using the phone.
Tweaking the app's configuration can also make a difference in both, user experience (how long it takes to switch back to 3G) and battery savings.
I did export the registry entries for it so restoring after a flash can be pretty simple.
Not sure if cooking it into a ROM would be a good idea or not since some will inevitably like the program while others will not. Just the nature of the beast, I suppose.
Thanks for the heads up, I wouldn't think of cooking it in but add a link to its download or upload to cab section for who wants to try it.
Very busy day at work today so tired