I have a 2009 and a 2011 model that both have the Vanguards on them. The only issue that I have had on them is the stator located under the flywheel.
As we all know, fert dust is hard on any equipment, especially a ride-on. This motor seems to suck it in and some ends up sticking to the stator coils(exposed copper wires). Oxidation eventually does it's thing and turns them green and well... I think you get the picture. I have right at 1000 hrs on the 2009 and have had my local service guy put them on parts/labor $120. I have had 4 of them put on during its time with me. This is the only issue I have ever had.
Z-spray used to build them with Kawasakis and at the time I purchased the 2009 I had a choice either/or. They told me they were having problems with Kawasaki and warranty issues so they were in the middle of the changeover.
I don't know, maybe fert dust was affecting them in some way too...
"The Poor Fish" circa 1930's: The Poor Fish wouldn't have been caught if he'd known enough to keep his fool mouth shut.