I just made the switch this month. Previously I had used a Surly LHT with 700x25 Schwalbe Marathons and Drop bars. to commute (13 mi each way). The new ride is a Surly Ogre w. 700x50 tires, upright Surly Open bars and a Rohloff hub. I commute over rolling hills in the suburbs west of Boston

My commute is not noticeably harder, it takes me 5-10 minutes longer (but my only experience on the new bike has been in very cold and icy weather so that may be part of the reason) The Rohloff has been stiff during the break-in, so I believe that has contributed to the slowness as well. I have found no ill effects from upright position; my butt, hands and neck are all happy. Blasting over the rough stuff on the side of the road has been a huge plus and the upright position is much better for appreciating the scenery around me.

All in all, I'm loving the switch and will not go back, even in the summer.

Steve