Nothing much. Had to replace a rear shocker for last years MOT and the rear wheel bearing has slight play in it.
The reliability is excellent. I can store it in the garage through winter, put on the battery and it starts first time. Admittedly the car only covers 1,500miles per annum, but its never even miss-fired.
Performance is acceptable even by today's standards and handling is excellent if not a tad heavy (no PAS).
Comfort is not as good as my E-class, but it's over 40 years old and all the wood and leather makes up for it.
Running costs are let down only by fuel consumption (20mpg) but classic insurance is cheap and tax is free.
Main Mercedes dealers are excellent. They can still order any part and are only too pleased help or offer advice.
I would definitely buy another Mercedes simply because of the quality and dealer service.
UPDATE: NOVEMBER 2005,
Car still going strong. Sailed through yet another MOT and still hasn't missed a beat.
If you ever decide on owning a 111 model cabriolet or coupe, you will continually enjoy the outstanding design and almost guaranteed value appreciation. These days of computerized cars, unless you do your own maintenance, you may find it difficult to find a mechanic qualified to work on the mechanical fuel injection system. The car must be driven, otherwise it is fairly basic and will run forever. It doesn't take kindly to being a garage queen. Keep an eye out for rust.
Just bought a 1962 rhd 220 SEb cabriolet garaged for years. Brilliant car. Love that six cylinder humm and smooth change of gear. As a boy I always loved the old Merc six cylinder slipping up through the gears and the mouth-watering interior of the coupe or cab. I can't wait for it to arrive!