To summarize my take, here's what I think.
- Yes, there is a donut hole.
- It's about affordability, not price competition.
- If it were filled, I'd probably move two of my legacy basic groups into it.
- If I were starting a new group and needed only basic features, I'd probably still go with GIO over Google (and live with the storage limits) - mainly because of the excellent moderator toolset and Mark's commitment to the product.