Managing rights for users on document level granularity was pretty easy in 1.6. A simple js function (it's called a "design document") to handle the logic and you are done. Just an example:

    function(newDoc, oldDoc, userCtx) {
        if (userCtx.roles.indexOf('can-write-sessions') !== -1 || userCtx.roles.indexOf('admin') !== -1) {
            return;
        } else {
            throw ({
                forbidden: 'can-write-sessions role missing'
            });
        }
    }

Why do you think that the Couchbase Sync Gateway is better?