I'm thinking about replacing the front rim of my Thorn Raven Sport Tour. This will be the second change. First 10000 miles were on Sun Rhyno. I've got Rigida Andra non-carbide and I've just passed 20000 miles. I think I've got another couple of thousand miles left in them, but have already bought the Rigida Andra CSS rim as a replacement. It's been sitting beside my desk awaiting its call of duty!
Incidentally, the original Panaracer Pasela tyre lasted longer than the Sun Rhyno rim: I changed it at 11000 miles. The current PP still has loads of tread left on it at 9000 miles' use. I use Marathons on the rear wheel though. I'm over 110 kg and PPs wear out in 1500 miles on the back!
My wife and I broke a Rigida Andra CSS rim on our tandem. According to Robin Thorn, they've never before seen one of these having been broken. Mind you, we've also cracked the flanges of 3 Rohloffs. The 4t, with reinfocing ring, has now had over 2 years' use and seems fine.
We got about 4000 miles out of Swissstop Blue blocks on the tandem.