I've been asked a couple times whether I did my recent California trip on a single-speed. My Surly Disc Trucker does have a single chainring and single cog, but the cog is attached to a 14-speed Rohloff Speedhub.
We've been selling the occasional Rohloff for years, but I never fully understood why anybody would pay the hefty $1300+ price tag for a gear-hub that seemed kinda heavy and potentially difficult to repair. But now that I've had one for most of a year, and have a couple longer trips with it under my belt, I understand. Rather than re-invent the wheel, so to speak, by writing a list of Rohloff benefits, I'll refer you to click here for a list of Rohloff's primary selling points. I'd also add that the Rohloff wheels are very strong because of the symmetric, non-dished spoke lacing.
We have lots of experience with internal gear hubs from Shimano, SRAM, Sturmey Archer, Nuvinci, and Rohloff. The Rohloff is, by far, the most expensive. It's also the only one that consistently lives up to expectations of the low-maintenance and long durability of internal gear hubs (IGHs). This is accomplished by being a sealed oil-based hub, not unlike a car's transmission. Many lesser IGHs let water and crud sneak in around bearing dust covers, and nobody notices until it's too late and the thing seizes internally with rust (we see this a few times per year). Because the Rohloff is sealed to contain oil, it's not possible for foreign substances to get in and cause damage. A second point to consider is that the shift indexing happens INSIDE the hub. It doesn't matter how dirty or kinked your shift cables get, or how much mud gets packed into the wheel, the hub will still shift perfectly.
The repair-ability issue is worth a mention. There are a few places that service Rohloff hubs, but most likely you'd have to send your wheel to the service location and wait while it gets repaired and shipped back to you. This may or may not present an inconvenience. The good news is that this is rarely needed. There are numerous stories on the web of cycle-adventurers and commuters putting 100,000 miles on a Rohloff without a glitch. You should change the oil though, every year or every 5000 km, whichever comes first. It's easy and inexpensive ($32 or so).
Anyway, a few years ago I might have told you that Rohloff was mostly a status symbol, since many cyclists know they cost a lot of money. I don't feel that way anymore. Compared to high-end derailleur drivetrains, the Rohloff is actually not terribly expensive. You could easily spend as much or more on a fancy cassette hub, cassette, derailleurs, and shifters, to have a less reliable, less durable, higher maintenance system.
I mentioned my Surly Disc Trucker earlier. Surly has been quietly putting Rohloff OEM2 mounts on several frame models, including the Big Dummy, Troll, Ogre, and Disc Trucker. The OEM2 mount makes Rohloff mounting easy and elegant by anchoring the torque of the Rohloff shift mechanism against the head of a barely visible M6 bolt threaded into a special fitting in the rear dropout area. My Disc Trucker is an amazing bike - tough, stable, comfortable, good at hauling weight on rough roads, etc. The Rohloff makes it even better. If I had your money, I'd get a Rohloff Ogre or Troll. Someday.
Speaking of someday, I'm trying to find a few people who are interested in a Rohloff group buy. If I order five Rohloff hubs, there's an attractive 10% discount off the wholesale price (which I'm happy to pass on to retail customer who participate in the group buy). Please contact me if you need a price quote, as there are MANY Rohloff variants, all at different prices. I can, of course, also build your Rohloff wheel and install it on your bike, if needed.