2007 is my first Audax year. I've done 2x100km and a 200km on my Raven Tour. I've done 165mile in a day (not Audax) on it and will attempt a DIY 300km soon.
I'm a slow, plodding rider on any bike. To me it's comfort that gets me to the end of a 200km not lightness. The Frame and tyres (26x1.5" Panaracer HiRoad)make for a stress-free ride.
I thought I may use my old 531 700C 'Audax' bike for the 100K rides but the Raven is just too comfy.
I use Drop Bars and hav eno problems with shifter on Accessory Bar, in fact it suits my riding style perfectly.
If you are more inclined to road-race, time-trial then a Rohloff is simply not going to suit you. If you want something to get you there, along a variety of roads (including pot-holes, tree debris and so on)and arrive in a degree of comfort then either RST or Tour seem ideal.
To me it's a Subaru Forester of a bike, ie. will cruise on-decent roads all day but can carry a load of stuff across rough tracks if required to.