The Greenstar lets you enter both field names, farm names, task names, product names, operator names, and machine names, whereas the PF3000 only lets you enter field names, crop names, and load names.   The Greenstar allows the names to be up to 20 characters long, and the PF3000 is limited to 8 characters.

The Greenstar will also let you do multi-product variable rate application, if you are running green tractors.

There are many valid reasons to consider a PF3000 over a GS1 if all you want to do is yield mapping, or you don't have green tractors.   I don't think the reasons listed here were entirely correct, though.