An estimated 4-hour battery life for the Surface Pros.
That's not bad considering the Samsung Series 7 which also uses a Core i5 processor get's about 4.5-4.75 hours with a much lower resolution screen (1366x768). If you want better battery life, you'll want to look at the Atom based slates which should get similar battery life to WinRT Arm based slates (as well as being much closer in price to the Arm based slates).
The price also compares favorably to the Series 7. 1,349 USD for the Series 7 with a 128 GB SSD versus 999 USD for the Surface Pro with a 128 GB SSD.
Overall you get more tablet for less money.
Personally I was looking at the Asus Transformer Book since it has the option of an additional supplementary battery in the keyboard dock. Unfortunately, it doesn't appear that it will have an active digitizer pen.
So, I'm back to looking at the Kupa which at least has a 16:10 screen ratio.
Anyway, breaking down the Windows slates.
Arm based slates are more suited to media consumption and casual use, so far. We'll see whether professional apps other than Office get ported to it.
Atom based slates are more suited to media consumption and casual use with light professional duties. I haven't even used my notebook when traveling after getting my 1st gen Atom based Slate. So for the past almost 2 years, my Win7 slate has basically replaced my notebook for on the go computing. It's noticeably slower than my notebook in some desktop apps, but makes up for it in portability.
Core iX based slates are far more suited to media consumption combined with heavy consumer and professional duties on the go. This will be my next slate.
Most people would do just fine with an Atom based slate. And I expect the bulk of Win8 slates (x86 based) sales to be there.
Regards,
SB