What is in the surface RT that would make it get worse battery life than andriod tablets ?
The rt has a 31.5wh battery and the pro has a 42wh battery. The rt is using a tegra chip , the tegra 3 or the tegra 3 + . The pro is using a ivy bridge ( i hope haswell).
So lets look at other devices.
The transformer prime has a tegra 3 its 10.1 inches and it has a 24WH battery.
http://www.anandtech.com/show/5175/asus-transformer-prime-followup/3
The transformer prime gets over 8 hours of battery life web browsing and 10 hours watching 720p movies .
Thats a 24wh battery vs the 31.5wh of the Surface. So even if the surface has more ram it should have similar battery life .
I think 8 hours + is good for a tablet.
The pro is going to be harder to figure out.
Take the mac air 11 inch
http://www.anandtech.com/show/6063/macbook-air-13inch-mid-2012-review
You have a dual core i5 1.7ghz ivy bridge. I personaly think we will be getting a quad core by the time febuary comes around. But regardless
Light work the 11 inch is 5 hours , medium is 4 hours , heavy is 2.43 hours
he describes his tests here
http://www.anandtech.com/show/6023/the-nextgen-macbook-pro-with-retina-display-review/16
Now the 11 inch has a 35wh battery obviously smaller than the 42 wh of the surface pro.
2.43 hours is ideal by any means , but anand is downloading at 1MB/s playing a 1080p movie in addition to what hte medium test does which is loading flash webpages every 10 seconds
So i'm assuming the surface will do much better playing back a video by itself or just surfing the web normaly.
I'd wager the pro will get 5 hours or so of video playback mabye 6 of surfing the web. Not a huge deal to me as I will simply get some form of extended battery for when i need more than that.