One of the aviation companies I used to work for had 4 C340's on their ramp. We serviced them in their operations which were privately owned business aircraft where the owners would make short haul trips around the region. I can tell everyone, we rarely had to do any major repairs to these planes. They were reliable as could be despite all 4 of them were quite aged and a lot of time on the Hobbs meters. I did get to fly one of the 340's once going with the pilot to pick up the owner at a location about 300 nautical miles out. Smooth ride, and good hand flier(we never used the auto pilot). It was much smoother and more stable than flying Beech Barons from my recollection.
The other story about the 340 is one about their typical hazard-the tip tanks. You had to be careful walking around any aircraft but the 340's tip tanks were at head level for average height people. One of my friends who is a member here was walking around a 340 before flight and managed to walk into the tip tank being struck dead on his forehead. He was knocked out cold! Another pilot had the same thing happen to him. A Cessna Conquest 1 Horizontal Stab leading edge got me a few years later! My caution level around Cessna twins is much higher these days!