Microsoft Surface - RT or Pro ?

So I've been interested in the Surface for a while now. I've had a play about with a RT model in a John Lewis store, tried touch cover there and found it to be a beautiful device. Over the last few months, I've become a big Windows 8 fan and I'm eager to bring myself into the Microsoft Eco-system. So here's my problem....which Surface shall I choose ?

I currently use a Windows laptop, an iPad 2 and an iPhone 4. I don't have much interest in changing to Windows Phone from my iPhone right now but I'm definitely interested in changing my tablet from an iPad to a Windows tablet. However, I'm trying to decide with I want a Windows RT tablet or a Windows 8 tablet. I'm going to be given a 2nd hand laptop pretty soon and I intend to install Windows 8 on it as soon as I get it. So would selling my existing laptop and my iPad to buy a Surface RT which a touch/type cover be a good idea ? Are the performance issues really as bad as they're said to be ?

I mostly use a tablet for consuming, but I don't rely heavily on apps, so the lack of apps in the Windows Store isn't a big issue for me right now, but what do you guys think, RT or Pro ?