Hello TLR,
Yes, I have a Tessina I've used for about 28 years. They are very precisely made. Always use a chain or wrist strap to hold or carry as they are smooth and slippery and easy to drop. They make a bigger negative image than a Minox so you get more detail. You lose about 1/8th of the image on the side the mirror meets the film. The image is reversed, so if you use an enlarger to print the negative you must print through the base side, scanning the negative provides more resolution. Any quality 1/2 frame camera gives a better quality image. Mine is totally manual so you have to set speed and aperture. You really need the prism head for accurate focussing. Virtually no one knows it is a camera. One person I was photographing from 1 meter away ask me if that item I was holding was a tester for Diabetes. It requires a special film cassette, but you can load any film you want, unlike the minox requiring a film slitter or special tanks to process. You can print two negs at once in a standard 35mm film carrier. It is not my choice if any other camera can be used, BUT it will get the image when no other camera can be used.
The price of a new one, I have no idea.
I have heard that the company that makes the camera is still in business. I've wanted to find them myself to send mine in for CLA, but have had no luck in getting a phone number or address. If you find out, please let me know.
All the best,
Sam H.