Business people that are travelling need access to email, MS Office, and the internet, and they need a real keyboard.

What good is a keyboard, if the Windows 8 OS ignores it and decides that you should use touch instead? The Windows8 interface puts off all users, unlike on a desktop, the interface cannot be replaced on a tablet, by installing 3rd party tools.

Corporation already use Microsoft, and MS has some good support for them.

You haven't lied, yet stayed away from telling the truth as well. Corporations use Microsoft software, but very very very few of them have gone with Microsoft Windows 8. The reason is that Windows 8 sucks big time in the corporate environment, it irritates the hell out of everybody. MS has stopped supporting XP, and tablets run only 8, so it's useless for them.

I gather that you disagree, but I'd like to know: have you actually tried using one?

I tried a Surface RT when it came out, could not join it to the Active Directory.
The Surface Pro2 was too pricey but the boss got one. Running regular MS applications on Windows 8 gave me a dirty guilty feeling, I didn't feel comfortable at all.
Atleast on a desktop with Windows 8, you can escape to the classic interface with some effort, on a tablet it is futile.

a medium-quality laptop and medium-quality Android tablet, both of which will be able to run Microsoft Office.

Some mfrs still offer tablets with Windows 7, so you can run a proper version of Microsoft Office on it. But the Surface Pro comes welded with Windows 8+, and that is useless for business users and business applications.

My uses, as an IT manager:
                      note taking in meetings with OneNote
IT Manager that takes notes? Interesting.

                      reviewing documents (Word/Excel/PDF)
For every Manager that reviews documents, there are a 100+ business users that create and edit them. Very painful on a tablet, even a Surface Pro.

presenting (PowerPoint)
Again, a small fraction of business users.

email (Outlook or Mail)
Very painful without a real mouse and keyboard, you can attach them to a tablet, but that's make it more expensive and more cumbersome than a desktop at a third of the price.

web browsing
Again, painful on Windows*+ versions of the OS.

cloud storage (OneDrive)
again, this is far better on laptops and desktops with proper network cards.

                      Remote Desktop (Citrix Reciever)
                      entertainment on airplanes: video, ebooks
A 12" device is more of a hindrance for these use cases. On a tablet 10" form factor like the iPad would've been ideal.

I do need to be able to run MS-Office compatible software on whatever platform I use. Microsoft's pitch -- "runs all your favorite MS software on your device of choice"

Ever tried running MS Office apps without a mouse?

Ever tried running your favourite MS software (I mean software developed using older versions of Visual Studio) on Windows 8+ versions?

Ever tried connecting a Surface Pro to your company's Active Directory and implementing GPO?

A $300 desktop does it very well, and a $500 laptop does it better, and is portable besides.

A tablet that doesn't win Windows 7 or XP is useless for business users.

just drop it into a cradle when you need a bigger screen.
People who use bigger screens also use the mouse extensively (navigating, point and click, highlight, copy/paste) and a proper keyboard besides. One would rather suffer dental surgery than run Office apps on a tablet device running Windows 8+.

Think Macbook Air with a detachable keyboard.

How many Macbook Airs are used as business machines? Less than 2% at a guess. So the Surface Pro 3 can aim for less than 1% marketshare in the business machines, since unlike Apple, the brand has less charisma than a donkey.

They're a fantastic business machine. They really are.

How so? What fraction of business users have even considered Windows 8 and above for their desktops / laptops? Less than 5%, if that. A business machine that cannot run Windows 7 or Windows XP is dead on arrival.

Only a foolish business user would willingly throw $700 for a device that lacks a proper keyboard, mouse or network card interface to the company's active directory managed network. Business users need Word, Excel and Outlook; they need to be able to run legacy apps developed years ago, that do not run properly if at all, on Windows 8 and above.

Unless business users can load Windows 7 on the Surface Pro 3, the device will lose another billion bucks for the beast from Redmond. No point having powerful hardware when the software sucks.

most of us artists prefer to actually see our lines appear where we are drawing them

Connect a touchscreen monitor with a pen to a normal desktop - problem solved.

Do you mean to say Microsoft is creating an entire range of device just to cater to the fetish of artists drawing and doodling? I wish them all the best of luck.

And smaller phones and desktop computer can't do things a 12" tablet can.

Can you please name a single thing or task that can only be done on a 12" tablet; and not on a phone or desktop? For your information, digitisers, pens and styluses are supported on laptops and desktops too.

they're going after the laptop market.... This will sell ridiculously well in the enterprise.

The laptop is a very long-lived well-researched device that has tons of applications available on that form factor. Running MS Office on a tablet device will have users tearing their hair out and getting aspirin tablets to rid their headaches.

Ah, you're one of those people with only half a brain.

Atleast I allegedly have half a brain. You are confusing creativity and art with a tablet form factor and stylus. Laptops and desktops support styluses, digitisers, pens etc. and have much more capable content creation software than those available on the tablet form factor.

Microsoft is saying they want to make a tablet that is good for content creation. That's why it's bigger. That's why it comes with a pen.

In my view, content creation is best done with keyboard, mouse and a desktop / laptop. What sort of content can be created with a stylus on a tablet? That's neither the best tools nor the most cost effective.

Cadillacs and Toyotas are both good at transporting people from one place to another. A 12" tablet cannot do most things possible on a smaller phone or a larger desktop.