Return to Ravnica is now available on Decked Drafter from the usual places (in-app database update for iOS, and from the Google Play store for the Android). As usual, the ratings are available now and we plan for the writeups to be available within the next two weeks.
A word from Marlon Egolf: Return to Ravnica is a difficult and complicated set to draft, so it is likely the ratings will change further down the road.
In addition, we have made the Scars of Mirrodin block entirely free for all platform users, so have fun drafting the older sets!
Good luck at your prerelease, and happy drafting!
– Tan Thor Jen