I can only echo the experiences of ‘LuganoPirate’. I have found both Lufthansa and Swiss to be nothing but exemplary in their service and when things have gone wrong they have worked hard to put them right while keeping me informed. I recently had a problem with a seat in Business on a flight to the Middle East, a couple of attempts were made to fix it without success and I was moved to First with apologies, a glass of champagne and a later visit from the CSD with an offer for a complaints form if I wanted. There was a follow up email from them a day or so later explaining what the problem had been (loose wire) and some points for my account as a further apology.
In my experience it is how an airline deals with things when it goes wrong that mark it out for good or bad (cough Turkish Airlines cough !)