I was on Opie. Why do you ask?
People feel free to correct me if I'm wrong.
I would have thought that the GPE version of OZ was a little more comparable to pdaXrom than the OPIE version of OZ, because both GPE and pdaXrom use X, whereas OPIE does not.
So that the GPE version would have felt more similar to pdaXrom than the opie version.
Therefore the OPIE version would have seemed a greater leap than if you'd upgraded from the GPE version.