Since I was granted the Lufthansa Frequent Traveler card in 2006/7 because I was flying to Hanover all the time, I have been using the relevant business lounges when I travel. These vary greatly in quality and some airports even make it difficult to visit them. In Bucharest, for example, you can only use the business lounge if you are a Senator customer.
Today I am in Zurich and sitting in the Arrival Lounge waiting for a colleague to arrive. A pleasant surprise awaits you here: the lounge is very well maintained and attractively furnished. There are only a few seats, but they are comfortable: 2 PC seats (don't forget the power adapter), 4x4 sofa seats and 4x4 seats. Plus the standard range of drinks and small snacks, with the coffee deserving of special praise.
Normally this isn't a reason to publish your experience on the homepage, but one thing really surprised me: in addition to the very clean and spacious toilets, you can use several shower cubicles with plenty of space and fresh towels. If you've survived a long journey and then meet customers, this is a welcome opportunity.
Another tip: Even as a customer without special status you can use the lounge for CHF 30.