RST because I saw a picture of if and thought "I want that one!", pretty much buying blind: a total impulse purchase!
I've not regretted it, the context being to date credit card touring to Andalucia (including light off-roading), Picos de Europa and Britanny and a daily commute of just 6 miles - wish it was more, sadly starting a job later this month where it's sadly a 25 minute walk, no justification for leaving my beloved RST unattended in London on a daily basis.
I think the all important factor to consider is whether you'll need to carry more than 17kg (max weight on the RST, 12Kg back, 5Kg front) for any purpose. I'm guessing that lightweight summertime camping is do-able on the RST, but for any touring that requires you to stock up on provisions, you're likely to need to carry more than this and thus a Tour is a necessity.
There's approx 1Kg weight difference between the Tour and RST, the other plus of the RST being a more responsive frame and ride from what I can understand, though I've never tried a Tour!