The Mint 16 installer has options to install alongside a previous Mint version, replace that Mint version, or custom partitioning.
Rather than replace Mint 15, the "replace Mint 15" option destroys all partitions and data. Well done, Mint devs.
At the very least, there should be a proper description of that selection. ie "this will destroy all your partitions" instead of the current BS description that's similar to "Deletes all Mint 15 files, documents and videos".
This lack of transparency destroyed my home partition, a Windows partition, a recovery partition, and a data partition.