I run a 46/36 crank with SRAM Apex 11-32 cassette, RD and Rival levers on a cross/touring bike. I have a standard XT set up on my Fargo. I run Shimano Ultegra STI on another drop bar bike. I still basically pick a gear and run in it and find no difference in my shifting patterns. The bar ends on the Fargo allow for trimming and if you ride in the dusty dirty stuff I find it helps. I run Woodchippers on the Fargo and highly recommend them and they work fine with brifters if you go that route. If you pick the proper crank gearing and match it with your rear cassette you can't go wrong with either setup just understand what you have and know they are different. Don't expect a 2x10 to be the same as the 3x9. Your riding destinations, terrain and preference will make the choice. I don't know what your brake choice is but remember the MTB BB7's are long pull calipers so if you go STI you need Road BB7's. They work much better.

Keep in mind the Fargo is an off road frame/bike. It will work on a paved road of course but its not a road based tourer. I'm currently running 700x40 Marathon Supremes instead of my 29er 2.0's to see how it's road manners stack up. It would work fine in a pinch but I like the 29er set up. That way it excels where you are on dirt/gravel and singletrack and run some pavement to get between those mediums. I'm probably going to buy a Vaya frame later this year after the new ones are available. Stay tuned for that new stuff later this month when Salsa makes other announcements. I think the Vaya and Fargo are different enough for me to warrant having something more road tourer oriented.