While the oplog does provide some semblance of RethinkDB's changefeed, it's not nearly as powerful. With Rethink, you say you want a query, and rethink will let you know about changes to that query. Mongo just says "hey, here are operations that were done", and leaves the reconstruction to you".
So I guess Mongo+Meteor match up with RethinkDB... sort of.
So I guess Mongo+Meteor match up with RethinkDB... sort of.