If all you want is a tablet, then the RT will be fine. If you need to install and run desktop programs you have to get the Pro. It isn't so much a matter of money as it is a matter of what you want to do with it. IIRC, the pro is going to start about $899, but again, it depends on what you want to do with it.
If you need to run desktop apps get a Pro or equivalent tablet. If you are OK with just running Windows Store apps, Office, and IE 10 then the RT should work just fine. I've also read that there are new tablets on the way that have Atom chips that should be priced around the same as the ARM chips but they also run desktop apps. That might be another option to think about.
From the specs they have let out, the Pro is also going to be a little heavier (1.5 pounds vs. 2 pounds) and a little wider and not as slim. These might not seem like big differences, but in my opinion the RT is about as heavy as I want (with the type keyboard attached) for a tablet, 1/2 a pound will make a big difference. Additionally, the RT comes with a 31.5 W-h battery and the Pro with a 42 W-h battery. That is about 30% more battery, but it will have to run a higher res screen and an Intel Core i5 processor. My guess is that battery life will not be as good as the RT, but that is just a guess.
I have a Surface RT and like it more every week. I take notes in meetings, read email and edit SharePoint documents. Also use Lync. For me it is perfect. Long battery life, instant on, reasonable weight. VMware will have View client out by March so you can run i386 apps virtually.
I have two surfaces. ( Is that Surfi ?) Two Surfi? Anyway, I purchased one for the house and was given one shortly thereafter to evaluate at work. I love the device. I must say however that I would Give them both back to have PRO device. As a tablet the surface has so impressed my housemate that she is in the process of selling her IPAD 3 and now only uses my personal surface. I must one day know why this forum hates multiple paragraphs. Ill take another arrow to the knee if need be!!!! ATT has a Samsung Ativ Pro for like 649 with a two year contract as of last week, so the lower end full blown devices are starting to show themselves.
I have an Ipad 3 and the Surface RT. I stopped using the IPAD since buy the Surface. Once I transfer all the information off the IPAD, I'll use the Surface exclusively. I do carry around an Ipod 5 Gen (5 MP) for taking pictures because the camera on the Surface (1 MP) is really bad.
It all boils down to this: do you need to be able to install and run desktop software?
If the answer is no - then choose Surface RT - you'll get everything you need in the store or via the web, and the app store market is growing rapidly.
If the answer is yes, then challenge yourself to really prove to yourself that this is the case. Take a look at the apps you'd want to run, and see if the apps in the Windows Store are actually going to do what you need. Remember, a Surface Pro is an Intel tablet, and will be heavier, thicker, and have lower battery life. It will be more powerful of course - and is effectively able to be a desktop PC when you need it to be, but if you're looking for that 'pure tablet' experience, then don't allow desktop software to compromise that experience - and go with Surface RT. I did, and I'm glad I did (I still have a regular desktop PC for the 'power user' stuff).
I can practically promise you that the difference will be more than $200, but the advice you have been given so far is excellent: The important consideration is what do you want to do with it? The most expensive device is the one you buy and it won't let you do what you need to do.
I bought the Surface RT partly for my own fun and partly to evaluate to see if it could be a replacement for my Ladyfriend's laptop that she carries when she travels to China. Conclusion so far is that it will not. The range of things she needs to do is greater than the Surface RT can provide. I will pre-order a Surface Pro as soon as they are available, as I suspect that will be the solution for her.
I bought an Ipad earlier for that same evaluation, and it doesn't even come close. I now use it almost exclusively as a reader. The singular, most important advantage of the Surface RT is that it has an actual, accessible file system and the ability to perform certain tasks (e.g., spreadsheets, word processing, etc.) and easily pass the data files between desktop and Surface RT. Surface Pro will increase that capability, even tho at the expense of a little more weight and higher cost.
There is a critical missing element on Surface RT that should deter all power road warriors - the absence of Outlook. The Home and Student version of Office 2013 does not include Outlook, and likely never will. If you are a hardcore Outlook user, look elsewhere (pun intended). The email, calendar, and people Metro apps are nice personal products, but they pale in comparison to Outlook, and are definitely NOT a sufficient substitute. Likewise, don't rely on OWA for a replacement - waiting on the Internet at times is like waiting on Gadot.
PS - my personal guesses are $999 for a 64GB Surface Pro, and $1199 for the 128GB version, IF we are lucky.
I think your price guesses will be right on the money. I intend to pre-order the 128G Pro as soon as it is available. I am anxious to get my hands on it, because I do think it will be her laptop replacement. You're also right about OWA; sometimes she goes to places where she simply has no internet access, so her device must be capable of performing stand-alone.
Evaluating the device from her perspective has proven to be very useful, especially as her travels often take her into rural and semirural China. For instance, she cannot rely on the hotel having wireless, so must connect via ethernet, if at all. Yesterday I tried connecting the Surface to my network using USB to ethernet. Can't get there from here. I am convinced that it is a problem waiting for a software/firmware solution, but, for now, it doesn't work.
Size and weight are important for a 5'2", 105 lb Lady who trudges all over China. Price is not a prohibitive impediment. She reminded me how it compares to the overall cost of her trip. Oh; ok.
I will look at competitive offerings while I wait, but still intend to pre-order the Pro. My first travel "computer" was a TRS-80, Model 100. My, my, how far we have come.
I have been using it as a laptop replacement for work on short trips and I have found the RT to be pretty useful. I will say the lack of outlook is tough, but OWA is a decent alternative, and I make do with the built in email for 90% of what I do. THe inclusion of word and excel is huge for me, I don't have to worry about not being able to edit a time sensitive document at the last minute and have formatting issues. Having a tab the size of this being able to do something like track changes in Word is a first. That combined with the type keyboard is great, as well as a real flash able browser. It's not 100% perfect, but its doing 95% of what I need to do, I can live with that 5% delta for the lower cost, size, weight and potential better battery life.