I've had an 8820, a 9500, and now a 9610. The 9500 will not keep up to a 8820. It is nicer to operate, and daily service is better, but if you can find a good 9510 in your price range, get it. There are many little things that they improved on in the ten series from the early machines that make it so nice to run. As for the grain monitors, you basically have to calibrate the sensitivity by looking behind the combine for each field, type of crop, or even size of cut, and deciding what is acceptable losses.