GPS/Autopilot dealer here rented space on local elevator leg & sells annual subscription. Signal will reach out about 12 mis on flat ground. If you're working in a rolling field, you may need a portable repeater. Repeater seems to get 100% constant signal when it's not moving vs the tractor/combine changing direction a lot. RTK signal he provides doesn't work on JD stuff.

I believe the advantage to using RTK will lie in the repeatability issue. It sounds like we may have the equipment draft issue addressed and perhaps on the way to a solution via Trimble technology. I'm sure others will follow.

It seems to me the cost of RTK was minor compared to other gps/autopilot costs. Not free-but not a major cost depending on your goals & desires.