I've had the Rohloff for about fourteen months now. I'm passed my first oil change. It's in a Thorn Enduro frame and is ridden 90% off road all year.
I bought it largely to reduce maintenance and trailside irritations on a daily off-road commute. So far it's living up to its promise and has been everything I wanted it to be.
I recently improved the rear end of the cable runs (pic here) to straighten them out from a large loop. This had an immediate and hugely beneficial effect on the friction in the gear shifter.


The dirt is pretty much 100% present where I ride, so I hope the oil seals are really up to the job. I NEVER clean the bike because I use it every day. The mud round here dries to a fine gritty coating which mostly would brush off if it ever got chance to dry.
So far in nearly 4000 miles, I have circulated 4 chains. They are all well past 1% elongated now (off the end of my park tools chain gauge), but the original Rohloff rear sprocket and Raceface front ring are going strong and I haven't even needed to turn them round yet. This is the sort of stuff I got the Rohloff for.
Performance wise, I'm really better off than with Derralieurs. I never notice any difference when riding with friends. Occasionally the slight whir (is it a drag or just a noise?) in gear 8 enters my conscience. Otherwise gear changes just happen without me even being conscious of them. Brilliant, no more clogged cables and mangled derralieurs. No more worn out jockey wheels. Instant gear changes are just so good.
I took it up Mont Ventoux in Provence last summer and was pleased with my 17.5" bottom gear, having needed it for nearly all of the 22KM to the summit!
I was a little concerned when my first oil change this December produced zero oil volume drained out. I read that this is quite common though. Perhaps I'll try the next oil change sooner than recommended.
I really like the triangular gear shifter and wouldn't change it, even if given the chance. It gives really good grip, even with wet hands, or in thick winter gloves. Gear changes are very natural and I am almost unaware of them. The rubber gear indicator letters have worn smooth now due to the edge of my glove, but that's unimportant. I can tell what gear I'm in and never need to look at it anyhow.