The John Deere rep is likely comparing SF3 to CenterPoint RTX. SF2 does not perform as well as CenterPoint RTX, but SF3 can get close as long as long term repeatability is not a factor. CenterPoint RTX IS repeatable year to year to 1" or 2.5cm, the same as RTK solutions, here are the specifications. Neither SF2 or SF3 provide or promote year to year repeatability.

Although Trimble's newest receivers like the NAV-900 do have performance improvements such as multi-constellation support, you can achieve the same 1"/2.5cm accuracy with CenterPoint RTX on any Trimble RTX capable devices.