The ARM-based WinRT tablets are the ones designed to compete with the iPad though, the Surface Pro is
not an iPad competitor, especially when the base model is twice the price of an iPad. It's priced to compete with Ultrabooks and the MacBook Air.
Even the base model of Surface running WinRT is $100 more expensive than the iPad, and that's without the keyboard cover.
If the discussion is ipad versus surface RT then I can't argue with you, but it's not because of functionality where Microsoft is winningo over plenty of critics with Metro. It's more because ipad has such an incredible headstart and such an integrated ecosystem. Still, IMO the Surface Pro will compete with the ipad indirectly, for those consumers who consider purchasing a laptop AND an ipad such as myself I would definitely get a surface Pro and save a ton of money. For me I look at getting a think laptop and an ipad at @ $2-3k versus just getting a Surface Pro which I'll assume will be $1k.
Once you actually start doing any kind of work other than browsing the web or typing documents, it's going to start getting hot & loud. The Surface Pro is basically the current 11ʺ MacBook Air inside a smaller enclosure, with a 20% larger battery.
I run photoshop on it daily and it still doesn't chug. I've even ran some games on it that surprised me how well they ran. I think anything more specialized than that like possibly engineering, CAD, high end graphics, etc are going to have a dedicated desktop or a much beefier laptop than the air.
And it has been shown time and time again that Windows has worse battery life than OS X. Depending on the model and task being done, it can be as much as 20% less, so expect battery life around the same as the 11ʺ MacBook Air when running OS X. (which is pretty terrible in my opinion, especially when compared to an iPad that easily gets 812 hours when doing anything other than playing games)
I'm not familiar with the studies you are citing (or aren't) but I've been using Windows on Apple's hardware for years and anecdotally I don't see a difference whatsoever. Windows7 is very smooth and efficient. Surface RT to the ipad should be very comparable in battery life, but I agree there will be some kind of trade off to run a full windows OS versus something like iOS, how much of a trade off we don't know yet unless we have a crystal ball hidden somewhere. For me I'd be willing to trade off battery life to be 5-6 hours on a WinPro tablet, which is about what the 11" macbook air gets anyhow. I have a feeling it will be more than that though, Microsoft seems to have come alive in a big way and they know if they drop the ball on battery life they will be sunk. I am also impressed by the perimeter venting http://www.youtube.com/watch?v=Ep9bem6O9r4 But once again we are only guessing until we see it first hand.
I can't imagine the Surface Pro replacing many people's computers either. You will need to be at a desk to use "classic" Windows apps properly (keyboard & trackpad) unlike a laptop which you can use anywhere without it falling over.
Maybe, it's a good point although I would never use a laptop actually in my lap for any kind of serious work anyway. Seems kind of moot to me unless you are doing some CAD work on the subway.
There are some great ideas with Surface, but I just don't think Windows 8 provides a good user experience either as a Desktop OS or a Tablet OS.