Pure anecdata from my experiences. The Rohloff is substantially cheaper as well as more reliable. I don't know how long a Rohloff lasts because I haven't worn the first one out yet.
Three Nexus 8 hubs failed at 5000km each. I had a Shimano Nexus 8 in a single-speed MTB fram that I commuted on for a few years. I only did about 5000km/year, the the hub only lasted a year. Fortunately Shimano replaced it under warranty - new internals only, so it was an easy swap. Unfortunately that one also failed after about a year. Even worse, Shitmano said "warranty replacement items have no further warranty" and even though I was still inside the original two year warranty, refused to replace it. Fortunately my LBS agreed to replace it at their cost. Unfortunately... that one also lasted a year. At that point Shitmano no longer made the exact hub that I had, the new Nexus 8 had the same name but different internals and I would have had to rebuild the wheel. So I sold the broken hub to someone who wanted it for parts.
In a bike shop I worked in we regularly maintained old two and three speed Sturmey-Archer hubs from the 1950's (and other similar hubs)and some of those had been ridden regularly for more than half a century. We were known as having a good supply of parts and knowledge so we saw a lot of them - people would travel some distance to bring their bikes in. Some of those hubs had worn parts that I didn't think would wear much at all, so they'd been used a lot.
The SRAM 3x8/3x9 hub gear with cassette is also fairly reliable, I've only seen one failure and that was major rusting caused by immersion in salt water. I do that to my Rohloff periodically (riverine bike paths with tidal flooding) and haven't had a problem, but I suspect it would be an issue for any of the non-sealed hubs.
My Rohloff has now done over 80,000 km and it's still making that slightly rough sound characteristic of the early Rohloffs. So much for "it'll wear in and get quieter". Maybe in another 100,000km? I bought a newer Rohloff for my partner's bike a couple of years ago and that one is quieter and shifts more easily.
I swap the Rohloff between my touring and load bikes (406 wheel rather than 559). Initially I was only doing about 2-3 thousand kilometres a year on that wheel round town, plus a tour, but they were hard on the hub - I regularly had rolling weights over 250kg and I'm a fairly powerful cyclist. Later I built a commuter bike and I use the Rohloff in that for my usual 6-8 thousand km of commuting as well as touring. I bought that hub in about 2001 and in 15 years I doubt I've ever done less than 5000km/year on it.
That's a metal tool chest weighing about 80kg on the back of a loadbike, with my Rohloff wheel under it. The burly guy riding it found it hard to hold upright... it was heavy.
There's my touring bike with the same Rohloff in it. Two large panniers, a backpack, 20kg of camera gear and assorted other stuff, all on that rear hub. I've probably done 10,000km like that.