The Advocate General's answers are out and though brief are a very insightful read. 

The key takeaways of this opinion are as follows:

1. Model clauses are fit for purpose; 

2.  A data exporter should stop exporting data if they know the data importer is in breach of/ can't comply with EU privacy law and, if they won't, the relevant supervisory authority should intervene to suspend or prohibit the transfer; and

3. A hint of a comment that could be interpreted along the lines of: anyone processing EU data is subject to EU privacy laws, this means you too intelligence agencies. 

The AG’s Opinion, while not binding, can be considered as an initial indication of where the CJEU will land. It seems that the AG's opinion is not dissimilar to Mr Schrems' arguments in this case

And now we wait for the CJEU decision on case C-311/18 - Facebook Ireland and Schrems at some point in 2020.