I had good experiences with the tags on my recent trip ^.

Bags came off quickly ex SYD to LAX, first 10 or so.
A bit slower but still with other priority bags ex LAX to JFK. The entire plane's luggage was slow on that flight (of course we arrived at 11pm ).

First few off at SYD (ex LAX).
Between JFK-LAX I didnt need to collect as they were connected through to SYD. So I was lucky that the bag arrived at all