Similar but from what I understand it allows granularity down to seconds instead of minutes and new cluster provisioning in minutes rather than potentially hours.
Speed of new cluster provisioning is neat, amazon-rds console currently shows the option to do a point of time restore down to the second. Maybe that's actually not available already and they're truncating to the latest backup?
Edit: I guess it's also nice that it's in place. Some people probably don't have the flexibility to easily point applications at a new cluster in a repeatable way, so that may help folks prevent down time.
Point in time restores to the last daily snapshot and replays logs since that snapshot; this can take quite some time (hours) if your database has a lot of writes, especially if the snapshot was 23 hours ago. The blog post doesn't quite make it clear but I would hope that backtracking is somewhat quicker than this method.
I think the main difference is that restore will create a new DB instance, whereas backtrack updates the state of the DB instance in place. It is also probably a lot faster than restoring.
Edit: Main difference seems to be new cluster vs. in place.