My view on this for best stability: don't fix what isn't broken.
If you want to be on recent firmware, you can go to the latest in the firmware train that you are in (16.06) quite safely. If you need features that are added in newer firmware trains, you can upgrade to a newer train.
Then as ariyap mentioned, for new deployments it makes sense to go for the most recent or the one before.
In larger networks I see many customers standardize on a specific release or firmware train, which makes it easy as commands that are introduced recently will then either not work (in which case you can plan an upgrade for the full network) or the work on all of your switches. Also all switches behave more similar than if you have widely mixed firmware releases.
In a standardized firmware version situation it may be good to evaluate every 6-12 months if there is a reason to change to a later standard version. Network management tooling like Airwave, Aruba Central can assist in managing this firmware versions.
So in summary: for new deployments go with the latests or before latest release; for existing production other rules may count and staying in the same train is fairly safe.