All battery saver in background does is allow the live tile to update it. If you disable it from running in the background, your battery saver tile won't update unless you open the app, so you could have full battery but the tile shows it almost depleted, as you last ran the app on low battery.
I have noticed little to non-discernible increase in battery life, with it disabled from background. Lumia 1520 (937) cyan firmware. This may be a problem specific to certain models, but I have heard say 1520 owners experience it too. It's entirely possible this thing is more pronounced on 925's.
It's a travesty that MS called this Battery Saver.
How is it a travesty? It kicks in at 20%, and it does indeed save battery. Therefore, its name is not a lie. It does make a difference. It also acts as a hub where the user can go to disable background tasks, further conserving charge.
Battery Saver does NOTHING until your battery reaches the default. Should have been more in line with like Battery Life Raft. Everyone thinks that if it's enabled, the phone will use less juice.
I'm scratching my head wondering if you actually use a Windows Phone device, because everyone here who's used battery saver knows you can manually turn it on at ANY charge level, allowing the phone to use 'less juice' across the board. That's hardly what I'd call a life-raft functionality, is it? If I turn battery saver on at 100% charge, it's doing
exactly what you're suggesting it
should do, which is use less juice
at any charge level.
The 'life-raft' scenario implies it can ONLY be used at low charge, which is simply not true, and even if it were true, I bet you most users wouldn't want it kicking in unless their battery were low anyway, because... why cripple the device when you have plenty of juice left?
Well, DOH, why wouldn't they just build that into the OS
Windows Phone is already one of the most battery-efficient OS, if not THE most efficient one. I think the battery life differences between the HTC M8 on Android and WP speak for themselves. What makes you think Microsoft hasn't already designed the OS to be as efficient as possible? Should they bake battery saver's enabled mode into the OS instead, so users can never get background tasks, period?
Furthermore, the reason why battery saver, by default, only kicks in at a low battery remaining, is so that people aren't effectively using crippled devices fresh off a full charge. iPhones do the same thing; they have a low battery mode, and a super-low battery mode below that. There's no sense in crippling what your phone can do unless you specifically need to do so.
One more time, repeat after me
Could your attitude possibly be any more snarky? Why do you feel the need to talk down to people?