I owned one, I drove it, and I disliked the experience. Mine was a 1980 convertible made at the Solihull factory, which were supposed to be some of the better cars. Alas, in a nutshell it explained why the company folded and never came back. The UK automakers generally refused to acknowledge reality that customers got fed up with terrible service and crummy quality. Triumph was an extreme example of British Empire hubris run amok in the automotive sector. They should have sold to Tata if they had the opportunity, just like Jaguar.
Somewhere along the way the previous owner of my car replaced the terrible factory electronic fuel injection with a couple of older carbs, which helped it run reliably. But overall the car was still a nightmare. Eventually the transmission self destructed, seizing up on me while driving down the highway at moderate speed. I’d never imagine my 74 Impala doing that to me and it never did even though it had over twice the mileage of the TR7.
The body itself was not very rigid, even by convertible standards. Slapdash construction and cheap materials meant potholes were a gamble - very easy to bend a shock tower without even thinking about it. Performance - ahem - of one of these cars (unless it is a TR8) is nowhere near that of a Miata so it’s no question that anyone looking for a weekend toy would be better off going with any example of Mazda’s little convertible.