I used a NH640 for about ten years with very few problems.I did have some trouble when it was new but learned a few tricks and rolled approx 12000 rolls with only minor problems. Traded in August of 04 for a new BR 740.I am very well pleased with this baler but I have several years of experience now with NH balers. Any problem that comes up I know exactly where to look and what to do, this takes time with any machine.One thing that gives trouble with NH balers is long stemmed hay that is laying flat and straight,it tends to hit the belt and try to shoot out the top of the baler. If you use a mower/conditioner or a tedder this will not come in to play.The tension on the belts is easy to adjust. The bales hold their shape very well