we have owned about 10 liebherr track loaders all between 1985 and 1996 models, they are good and easy to work on as far as i'm concerned, but the 631 is my least favorite, in the 2 smaller models they will push as good as cat of the same age and size but a 631 won't keep up with any 963 on power or speed. still for the right price and if you aren't running it everyday it would be a fine machine.