The 8560 is a good reliable combine,the only problem with it is that it is a little shy on horsepower.It is also very easy to work on.The 8570 is pretty much the same combine with some improvements to the main machine but the biggest improvement is a lot more power.If I were you and wanted to trade up,I would trade your three 750s for two 860s.You would only be running two combines instead of three and getting more work done in a day.