Sonosax and Nagra are quite elegant. I would first opt for the Nagra as it has a track record of working, regardless. And the electronics in it are first class. The drawbacks for me are the price and the lack of a local factory repair site. I understand that Nagra has a couple of good authorized facilities in the US. I am not sure about Sonosax.
As for Cantar, well, French women are really so enticing, eh?