After using an Insight for a few years, I got an EZ-Guide 500 with EZ-Steer for another tractor which is used primarily for tillage.  I couldn't believe the difficulty I had in working with the Data Structure (or lack of it) and managing the AB lines in the 500.

I guess I just got spoiled by starting with an Insight.  The Ag Leader system seemed so intutive and I felt that I must be missing something in the Trimble unit.  With the Ag Leader system the AB lines can be named when saved and are associated with the field in which they were created. With some trickery, they can be moved to adjoining field if you really want to.

I really just gave up in trying any type of data management with the 500.  Later, I switched this tractor from EZ-Steer to Autopilot.  This worked fine, but of course, did not change the situation with the AB lines etc.

When the CFX-750 came out, I had an opportunity to trade the 500 for one.  The CFX-750 is easier to naviagate through the menus and has some other desirable features but doesn't seem to offer the ease of working with the AB lines that I desire.