I've just spotted that we now have access to ETS rater; and have started to investigate it. 
From what I can see, it's not available to students pre-submission - though i see that Draft Coach is (if you are a Google University). 
So - a few questions: 

• How does the ETS rater evaluation compare to the Draft coach feedback (for those using Feedback Studio, rather than the newer TII offerings. 
• Will Draft coach be coming to non-Google users (and/or ETS rater to the pre-due date view students can get of their work - like the similarity report)?
• Can I double check that Draft Coach doesn't cost extra ££/$$/€€ / whatever else you typically spend! 
• Has anyone compared, from a student view point, ETS rater / draft coach / grammarly (free/paid for versions??)/the grammar checker in Word etc [A colleague has just asked me that!]

Thanks