I ordered one the first few minutes of the preorder, but I'm almost certainly going to send it back on arrival - I can't find any way on the microsoft store website to cancel the order.
Background: I have a Lenovo X220T (convertible tablet/laptop) that has been running Windows 8 since Jan. The reviews thus far have hit on two of my biggest concerns about Surface and Win8 tablets in general - the form factor and the apps.
Form factor: My Lenovo been great as a laptop, but is too heavy and cumbersome to be seriously used as a tablet (see my comment to this post -
http://forums.windowscentral.com/1720497-post7.htm) My hope was that Surface would solve this problem, but it appears that they haven't, and I think it's likely an inherent problem with the aspect ratio. My Lenovo is too tippy in portrait mode (the height makes it hard to hold stable, and tiring as well), a problem that was echoed by the Surface reviews. In landscape mode you wind up having to hold it one-handed with that massive width providing a lot of leverage for that weight, while tap-tapping at the on-screen keyboard with the other hand. The split screen keyboard that allows you to type while holding it two handed seems like a great solution, but in practice it is very difficult to use because each hand is simultaneously trying to hold the tablet stable and move the thumbs around to type. I think this is why the reviewers universally complained about the weight even though it's essentially the same weight as the iPad - that weight has much more leverage because of the form factor. This all means the flipstand and floppy typing covers become essential to actually use it, except that you can't use it in your lap because the flipstand has a fixed (steep) angle, and the typing cover is too floppy. But if you have to set it down on a desk or table to use it, then what you have is not a tablet, what you have is not even a laptop, but a very underpowered (but very light) desktop machine.
Apps: I was hoping that WinRT would be capable of running WP7.5 apps, but that doesn't appear to be the case. The lack of apps is a killer. My Lenovo has an i7 cpu so it is running full windows 8, so applications aren't a problem. The Surface has only a handful of apps. Microsoft really shot themselves by not supporting WP7.5 apps on WinRT. The iPad may have only had a handful of apps when it launched (I had one of the early ones), but it could run iPhone apps to help tide its owners over until the market matured. The WinRT market will improve over time, but Microsoft needed a huge wave of customers that would be enthusiastic enough about their product to rave about it to their friends. Without a huge wave of WinRT adopters, there's relatively little incentive for developers to write WinRT apps. Windows 8 machines will run standard Win32/Win64 apps just fine after all, and those apps cannot be easily ported to WinRT. So to justify that effort, developers need a good solid market that can only be satisfied with a WinRT app, which means a large customer base that can only run WinRT apps - i.e. ARM tablets. x86 tablets and laptops don't provide that market - they're already served by traditional windows apps. It's a chicken and egg problem for Microsoft, as it was for Apple, but Microsoft completely missed the plot. Without that initial catalog of apps, WinRT is in the same position that WP7.0 was two years ago, and facing the same long hard slog.