Mine's been pretty dependable, but I'm a bit disappointed in the mud/snow traction of the R4 tires. Tractor wants to "walk" sideways when it moves at all. Diff lock doesn't seem to help. Only actual failure has been the MFWD sensor, which I've read seems to be a not uncommon issue. (Err06). Found out the hard way that there's fine print in the warranty that only gives electrics/electronics a one year warranty. It was an unexpected $400+ dealer repair, that I later found out I could have done myself for $86.
//greg//