I've owned the original 70-200 f2.8L AND the 400 f2.8L.... Both of which I've owned since the early 90's. I've never had any problems (knock wood) with the 70-200... It's one of the most versatile and durable lens there is.... It's never been into Canon for anything other than a quick clean and check.
My 400 is the same way... The only time it's been opened up by Canon is when the AF motor screws were loosening up and I couldn't AF or manual focus. The tech told me that he was very surprised to find out that it never came into Canon for anything... I think that I've been pretty fortunate that I never had any problems with it. I shoot sports from rodeo to football in all types of weather...
Both non IS lenses are fine pieces of gear IMHO...