Salary very variable indeed. You could be around 6500, before Swiss tax if you're lucky with your base, but you can also be just over 5000, before taxes.And don't expect to choose your base.
Then, for the guys with bad luck (with ETOPS contract), you still have to deduct 300 every month (agency fees...). Then, yes, you pay your accommodation, transport, commuting. For Western Std, not enough. But more than ok for East. Europe, if you compare the average salary around here...
'quite agree with the analysis of enemymine above..