Here in Australia mud buggies / chaser bins tend to get a hard life due to higher harvest speeds and often large paddocks to travel accross and axel failures were very common in the early days. About the only cart that has come into the country and has kept a reasonable reputation is the Kinze. Not to say the others mentioned are not good but just from my experience and observations of those I have used as a contractor. The Finch buggy has a very good reputation for staying together and handling our conditions. They also make "Mother Bins", these are moveable when empty and can hold well over 100 tonnes of grain.