We have replaced our Shimano gears for the Rohloff gear after having broken our chain once (2 persons 20 kg luggage +Santos bike) also being fed up with the maintenance after each ride on dirt roads. Changing gears uphills requires some coordination and sometimes strength to change gears. We are extremely happy with the investment! Another importance advantage is that while standing still you can change gears for a quick start (take off the pressure from the pedals though)

We were new to tandem riding 3 years ago and bought one Rohloff equipped from SJS.  After a few rides I stopped telling my stoker/wife about gear changes. She just sensed when a change was coming. I eased off the pressure very slightly for a split second, except for the 7/8 and 8/7 changes - a whole second, otherwise you could find yourself in 1 or 14. Being a bit ancient, we had very low gearing and on very steep hills it was easier to walk once you got down to 2 but I guess we should have changed the gearing, an easy job.  I liked having 14 equally spaced gears with no near duplications. It stays clean. Annual service is easy. It puts all the weight in one place which makes it feel heavy.

My wife and I used a Rohloff for a number of years, including tours to Italy and Dresden.  We found that the Captain taking off the pressure was sufficient to change gears.  The only time I would call out was when there was a sudden change in gradient, and I would rip 3 or so gears in one change.  This is a great feature when you have a stoker with suspect knees and a derailleur getting confused with too rapid changes. 

Our new Pino has a derailleur, and I regularly make a hash of it.  Lots of crunching and grinding.  We loved our Rohloff.  Even I could change the oil once a year.

We've had our Thorn Rohloff tandem for a few years now and for touring its hard to beat.  We've undertaken four 600-800 mile tours and I probably only look at the chain once or twice in that distance, I think I've only had lubricate and adjust the chain on the longest of those trips - at about the 600 mile point (I thoroughly apply wet lube before setting off), this despite cyclying forrest racks in wet muddy and dry dusty conditions.  We probably carry around 30KG of luggage and will tackle any hill, but I always call 'gear change' when changing down so that we can reduce the pressure on the hub, like Deon, I'll drop 2 or 3 gears on each change when going uphill.  On the flat its easy enough to change a single gear with the captain taking the pressure off for a second, however, I still tend to call out on down-shifts and occasionally on up-shifts as it warns the stocker whats my intention is. 

The only down-side to the Rohloff is a slight reduction in the range of gears over 3*9 Shimano LX gearing.  I'm happy to sacrifice lack of top speed for the reliability, we can climb a 25% gradient and still have a 20-22mph top speed (compared to maybe 25-30mph on Shimano).

Go for it and enjoy Iceland!

As with the other replies, if you've got the possibility for touring, go for a Rohloff. Especially with the strong winds and rough roads you can encounter in Iceland.

The slight restriction of range is a minor loss. On drops, a hubbub extention is not bad for the chager, though not ideal on steep hills if you are tired. But I often change 4 or 5 gears at once - without verbally alerting my stoker - on switchbacks changing from downhill to steep uphill again.. The Rohbox changing options sound interesting too but more hassle as a retrofit.

When it's not loaded, I do find the extra weight of the Rohloff an extra minor problem on the tandem, when manoeuvring the bike, because this weight is all at the back - further from I am standing. But with luggage there's no question of lifting the far end of the bike anyway.

Have a great trip and let us know how it goes!

Thank you all for the helpful information about how you each use the  Rohloff gears. The total enclosure does seem very attractive for Iceland given the wind blown volcanic grit.

We have just joined the club so sorry this is a bit late. 

Having used a standard chain/gear Burley Softride tandem for over 20 years we bought a Landescape Rohloff Belt Tandem a few years ago.  Gear changing is no problem; I am a lot heavier than my wife which may help!

The big advantages for us are the ease of popping into a low gear when stationary after a high-gear descent etc and the clean oil free packing of the bike inside our estate car for trips away.  I used to have to carefully wrap the Burley to keep the chains/gears safe from luggage but no more.