We've had our club's 1984 TB-20 for quite a few years now. I love the plane, though I liked our 182Q better before it got destroyed. Dispatch reliability has been about average. It's very comfortable to fly, with great visibility. Our annuals have mostly been under $5k, though I think we've had a couple well above that, not for just the annual itself, but from getting other issues addressed. It doesn't get a ton of use, as only about 6-8 of us out of 60 members fly it regularly. Early on we had issues with engine vibration, but that's common with the type. And the King 150 AP should have been replaced years ago because it seldom worked correctly for very long, but members didn't want to spend the money for a replacement. We finally got a GFC 500 installed, and I couldn't be happier with it. A few years ago, a number of members were advocating to dump the airplane, and we would have sold it to you cheap. However, before we could list it for sale, the engine threw a rod, so we got a new engine, and with that invested, decided to keep it. The airplane is valued at $110k on our books, though I'm certain resale value in the current market is considerably higher. With that said, I think that one in Camarillo on TAP which someone posted above, is way overpriced for a mid time engine and old avionics.
Our maintenance costs have been in line with our other airplanes. On a few occasions, we've had to wait for parts from France, but most things are available in the US. Ours is maintained by Luke at KFZY, who previously owned a TB-9 (or maybe it was a 10, I don't remember) so he was already familiar with the specs, and he had no trouble getting up to speed on it. He's said it's no more difficult to work on than a Cessna or Piper, keeping in mind everything is metric and the French designed some components a bit differently than US-manufactured airplanes. An interesting note, I was traveling in the midwest with the airplane last month, and had a gear issue, so tried to get the shop at a decent sized field in a large city to look at it. They immediately declined, said they'd never heard of a Trinidad and wanted nothing to do with it. (I did, however, locate an A&P at a smaller airport 20 miles away who said he used to maintain one years ago, and was happy to look.) As for insurance, hard to say, in the club environment, but from what I'm told, not much different than any other SEP HP airplane.
If you're serious about it, I second the recommendations for the Socata.org website and Bill Bennett's book, which I believe he just recently updated, for a good overview and discussion of the plusses and minuses. If you're interested in checking out ours in person at Freeman Jet, sitting in it or going for a ride, shoot me a message.