I guess I've been happy with the accuracy, using the Terrastar correction on the 6500.  I've made lines based on boundaries from previous years' planting that I use for autosteering the first headland pass in the field every year since, haven't autosteered the planter into a fence post yet at least!  I know they say you don't get year to year repeatability with Terrastar but it sure seems like I do.

This is using the same tractor/steering setup (ontrac3) every year.  I'll be curious if the lines are still accurate if I upgrade the setup and use the old lines.