Just upgraded from Cinnamon 15 to 16 on a multi-boot deskstation, and it wasn't a smooth experience.
I had Win 8 and Mint 15 on 2 partitions on a SSD.
What I wanted to do was overwrite my old install with the upgraded install, which must be a very common scenario. But this wasn't offered.
To achieve this, I had to find the other options dialog, and use its less than intuitive interface to select the partition, figure out how to set it to reformat, select a filesystem from long list of options, and manually set the boot directory - all of this without any guidance from the GUI. As a long-time Linux user, I was able to fight my way through and get set up. But inexperienced users would surely find this totally baffling.
Given that your core market is the less geeky user, I would suggest that this is a pretty major weakness in your install wizard.
I see from the forums that people have run into this issue with previous releases going back some time - and that it has baffled even hard-core developers. If you really want to be a user-friendly distro, perhaps you would consider addressing this issue?