Got mixed feelings here as well.  We have two 08 9770 combines with them.  The first one was bought new and we bought the 2nd one with a 100 hrs on it to help finish harvest in the fall of 2008.  The first one had the whole engine replaced before even got to us.  The dealer was doing the break in procedure and noticed burnt spot on the side of the engine block.  Called up Mother Deere and they sent out a new engine.  Last year during the summer, we get a call from the dealer to check the serial number of both combines.  JD had a PIP or recall and cylinder liners on a certain batch of engines didn't have the correct clearance or something along those lines.  The first combine fell into that batch of bad engines so the dealer came and got it.  Tore it down and pretty much rebuilt it.  So 2 out of 3 years that combine has had major engine problems but it has never cost us a second's worth of downtime in the field and JD ate it both times which according to what I have read on here the past 3 days, that might surprise some people.  The other combine has not given us any engine problems.