[Tilt, TyTN II, MDA Vario III Themes and Apps] newb5000:
In one of Mike Calligaro's posts, he talked about Suspended vs Unattended, since SmartPhones don't have a Suspended state, i.e. they are always on, whereas PocketPCs do have a Suspended state.

SmartPhones have smaller screen sizes and thus can afford to be "always on". PocketPCs have larger, touch screens, with large backlights, so Suspended is the way that they save battery.

There are advantages and disadvantages. For instance, when resuming a PocketPC which was in the Suspended state, you notice a lag until everything redraws and powers up (2 or 3 seconds for me). Waking the device from Suspended mode is actually a lot of work since a lot needs to be resumed. If the device was in the Unattended state, there is no need to wake up since the device is already awake. No drivers need to be resumed, no running processes need to be resumed. Thus (and I did notice the difference), when pressing the power button to turn the screen on from Unattended mode, it's pretty much instant. So resuming from Unattended uses less battery than resuming from Suspended.

You must remember, that in unattended mode, most things keeps running. All it takes is one app to say to the OS that "I need unattended mode", then the OS will override the behavior of the power button and what happens when the system idle timeout is reached. So if you already had Push Email or Windows Live Messenger running all the time, then they have already instructed the OS to go into unattended mode instead of suspended mode. In that case, you should not see a difference in battery life.

The difference in battery life is when CellID Updater is the only app that requests unattended mode, i.e. you did not have any other apps requesting unattended mode before you enabled that option in the app.

That difference is going to be very user and device dependent. The reason for this is since most things keep running in unattended mode, even CPU intensive apps keep running. It will definitely depend on which apps you have installed, how many CPU cycles each app uses and how much the ODM optimized drivers for the PocketPC. In general, if an app "polls", i.e. it checks for something every x amount of seconds (or milliseconds), that burns battery. If an app displays an animation, that burns battery. If the app continues to display the animation even though the screen is off, that will still burn battery life. So as an example, CellID Updater might request to run in unattended mode and not display any animations, but other apps might continue to display animations, which is bad.

I've tried to make the app more "battery friendly" since the last update and will continue to do so, but the battery life really depends on which apps you have installed, the current ROM, radio, etc.

My only advice (besides you experimenting with the option enabled / disabled) is that if you already have Push Email or the messenger app running continuously, then go ahead and enable this option. You shouldn't see a difference in battery life. Otherwise, you should determine if sending web updates about your current location is more important to you than battery life. I for example carry my usb cable with me in my laptop carry bag to work so that I can charge at work. I have a car charger in the car and a mains charger at home, so I can pretty much charge my device everywhere.

The nice thing is that unattended mode is configurable in the app, so if you know that you won't be able to charge over the weekend, for example, it might be better to disable that option (maybe temporarily).