Having sailed once in the Garden Villa, it's something we'd like to try again, but probably will only happen through bidding for the upgrade.
If after the cancellation date our family is in 2 separate cabins, and one of us wins the GV upgrade, am I right that the second cabin people would still be stuck with their costs for their cabin if they canceled it to join us in the GV? That would be the biggest reason not to bid for a GV upgrade as we'd have to figure the cost of that original cabin on top of the bid.
Only way around it I can think of is for the second family cabin not to be booked until the GV upgrade is unsuccessful, but that carries its own risks.