FOP2 not being officially supported only means, that you won't get support from Schmooze on it. This doesn't matter, because you will get excellent support from the FOP2 developer.
I am using it for a 1200 extension environment and it works very well. I have it on FreePBX High Availability, which required a slightly more complicated setup, but the developers helped me out on this.
It is inexpensive and what is really nice is that the developers make a good effort to implement customers' feature requests. I alone had about 10 of them, which got included in a matter of a few months.
It gets updated frequently too.
However, you need to find out if FOP2 already supports Asterisk 13, not sure about that.
In fact, this "not officially supported" thing scares people off otherwise perfectly useful 3rd party software, which is really sad in my opinion.