Where's the option for neither?
No RT device is more capable than the $800 thin and light laptop I bought in 2010. It would be redundant to keep that around if I'm getting a 10+ inch, $500+ device, and buying a decent ultrabook would add another $1200 at minimum. While I believe the Metro interface is quite frankly superior to what iOS and Android are doing on this kind of form factor, the app situation is just awful. For the few times I've poked my head into the Windows Store, I leave disgusted. As is, there is absolutely no way I can recommend an RT device over Android or iOS, unless the only thing you ever, ever do is run Microsoft apps. (Even then, many of the built-in apps are far less mature than what competitors offer.)
Microsoft may be boasting 100K+ apps on the Windows Store, but the quality is worse than Windows Phone in early 2011. Maybe Windows Phone is starting to gain traction because it actually has crossed some preliminary app gap. Windows 8's ecosystem feel years behind in comparison.