Two other options come to mind that you may be interested in exploring. Blocks and recording history. If you want to have multiple instances of an object and edit one with the others updating, that’s what Rhino calls a Block. You can read up on how they work here… http://wiki.mcneel.com/rhino/usingblocks
Recording history is an option at the bottom of Rhino that can be clicked once before running a command like say Mirror and then that Mirror action will record a relationship between the original and mirrored object allowing you to move the original to update the mirrored copy. You can also right click where it says record history to always record history when running a command. Not all commands work with history though and if a new object is created (e.g. BooleanUnion), a history relationship may be broken.
Personally I like GH for parametric modeling. It allows for a number of workflows and can be used in whole for a design or in part over small areas of a model.