For 'B' Permit holders who have been resident for longer than 1 year, I've been told it's 18 months unemployment benefit at 70% of base salary, 80% if you have children/wife, with a maximum of 7000CHF monthly.
In other words, a lot better than the UK, but the proviso is that Swiss companies do not normally give Severance pay.
Info comes from ex-pats who lost jobs after Swissair collapse.