The JTAC recommended release article is prepared by the support team at Juniper. They recommend releases by platform based on their experience with call volume and reported critical issues.
As a result this recomendation will never be the newest release. They update only after versions have been in the field long enough to have valid data for a selection.
Running the newest release gives you all the features as soon as they appear. Running the recommended release generally gives you a solid feild tested version. That is your basic choice.