Hi, just wanted to add my two pence.

I am a junior post-doc at ETH Zurich and I've been here for nearly four months now.
The deductions on my salary are about 23%. It's true that I'm not paying health insurance because of an agreement between Italy and Switzerland on this, but still it's quite low compared to many other countries.
From what I've experienced in these last four months I'm way better off here than any post-doc in UK, even with more experience than I have. On the other hand, I am on my own so my salary has to be enough only for myself. Anyway I can afford a decent flat, I furnished it and I can treat myself to a few extras I probably couldn't have afforded with a post-doc position anywhere else in Europe.
The downside in my opinion is that it's not very easy to start having a social life here, but maybe having your family with you would make things easier.