I would recommend upgrading to the latest available "General Release" of a supported Aruba OS for any given platform (Such as A3200).
There's no release which is an "Ideal" candidate or termed as "Stable" release, rather stability and best-match is highly dependent on two main factors.
1) What are features which we are planning to deploy?
2) What are the features listed within the "Known Issues" section of the release notes.
When we overlook this portion and stuble upon either the known or new anomaly, the image is thus termed unstable.
I suggest a reference to the below article,
http://community.arubanetworks.com/t5/ArubaOS-and-Mobility-Controllers/Memory-Upgrade-Required-for-3200-before-AOS6-upgrade/td-p/21156
The A3200 is going to require an XM memory upgrade to run 6.2.
Recommended to review the release notes of the latest 6.1 ArubaOS (6.1.3.9) release notes, ensure that the features which are meant to be deployed are not listed within the 'Known issues' section and then roll out.
It is ok run an older 6.1 version as well, as long as there are no known limitations which are blocking the desired config meant for the deployment.