I am still getting a feel for the JunOS release process. Of the two available releases for the EX4200, which is less likely to have problems? Choices are 9.5R3.7 (30 Oct) and 9.6R2.11 (8 Oct).
It seems that the two parallel streams don't really seem to stay in sync, for example PR/313195, an annoying superfluous syslog message that has been in JunOS for months, since at least 9.4, is listed in the outstanding issues for 9.6 but not 9.5. Who knows, maybe it's fixed in 9.5R3.7, which is more recent... The list of outstanding bugs in "outstanding issues" seems to be pretty evenly distributed between bugs which are present in 9.5 only, in 9.6 only, and in both releases.
The the minor releases still appear to be on a roughly quarterly schedule.
I think the best course is probably to stay with the the 9.5 stream as long as possible, unless there is a feature we need. This is what I would do with IOS; there are usually huge differences between IOS "maintenance" releases (the number after the decimal) , and very rarely regressions in the "individual" release numbers (the number in parentheses.).