I was in Munich over the weekend for a stag do with some friends. We were surprised that the U-Bahn was running stock which looked like it was from the 50s or 60s...but you know what? It was clean, it was comfortable, it was roomy and it ran on time. Perhaps a case of "It if aint broke...."
We only used the S-Bahn a couple of times (from the airport to the centre), and yes, the stock was old, but it didn't seem too shabby - again, clean, comfortable and punctual. Perhaps we were lucky enough to get a newer train.