I am in the exact same boat. I am going to be looking hard this winter at upgrading to either a 760 or 780. I want the wide body machine for the larger cleaning area in canola, and I want the tracks because of stability and fewer chances for flat tires. Also, I am sick and tired of broken bolts on my duals. I know they have fixed the issue on the 700 series, but I am now gunshy. We have replaces 4 sets of wheel stud bolts in 3 years, and I have a broken bolt on the other side right now. That will be 5 times in 3 years that we have had to fight those tires on and off! Anyways, I think there are enough improvements recently (i.e. cruise pilot and cemos auto) to justify a new or one year old machine. The increased acres a person can cover compared to a 580R should be significant.