Hi and welcome!
I've owned a couple and quite liked them. They're certainly durable, especially with that steel cage which also makes them heavy. Gear changes weren't too bad at all, a bit 'agricultural' but seemed better than earlier mech's like Euclid. If you're using a Campag cassette, the ExaDrive version with the profiled teeth makes a big improvement to shifting.
I think they sold for over £60 BITD