Seems obvious to me
All the platforms are good for tablets, but to me, any of the 'big 3' (Android, W8 and iOS) reign on different form factors.
I mean, If I were to get an Android tablet it would be 7", and only that. It works really nice for reading (Kindle, B&N and something for .epub/pdf files), and if it renders well (i.e not pixelated like iPhone apps on an iPad) it would be fine for phone-apps too. You do not get this on 10" android tablets, and due to their 16:9 nature, portrait mode doesn't work as nice as the iPad or 7" tablets (which are 16:9 too).
iPad? Yeah, the iPad. Before it, I really was with the anti-iOS crowd (not Apple, I always liked iPod Classics and Macbooks) on Engadget. I hated it till about sometime after launch. Suddenly, I "got" the device and bought the 64GB Wi-Fi version in 2 days, which is a big buy for someone my age. (even more so 2 years back) I don't know what it is, but it just works as the ultimate couch or, even better, fatboy-surfer. Not that I really like Apple that much as a company, but I like the iPad.
Now, if you want a heavy workload, do-everything tablet (which is what I'm looking for in a tablet), then an > 11" x86 Windows 8 tablet is the best choice. I mean, see how it works compared to the iPad? Or desktop mode for when you really need it. Or maybe Photoshop/OneNote/a finger-friendly DAW. A laptop dock with a dedicated mobile GPU (I can dream, right?), and you'd have perfect versatility. WiDi to your TV set, and use it as your media center with perfect playback*. You can do pretty much everything.
This is why I have an imported Nook Color (waiting for CM9!), an iPad and will be getting a W8 tablet.
*Plus, my TV-provider allows me to watch TV on a Windows machine when I'm on my own WiFi network.