A few days ago, there were news that Mint 18.1 was out and ready for install. This morning, my update manager prompted me to install the MintUpdate package, a sign that the new version is ready for prime time.
The release notes do not show anything that would affect me, and so far, so good.
The overall feeling is that nothing really changed: visually this is still the same, the system does not seem to be faster or slower.
A good point: the upgrade did not remove my PPA and other additional depots. It was one of the many little things that made me cringe during the update from 17 to 18. It is not very hard to put back (all the information is in ~/Upgrade-Backup/APT/sources.list.d) though.
Comment if you have had any issue.