Went from 2018.50.6 to 2019.5.15 today.
Besides the well-discussed changes, I’ve noticed that autopilot seems to change lanes more aggressively - it definitely picks up speed immediately (if needed) and it is able to merge into the next lane from a near-standstill in a traffic scenario without causing slowdowns in the new lane, but I had one lane change where it started speeding up and then slowed down immediately because there was a car maybe 1 car length ahead of the car I was passing (pretty sure it was shown on the screen so the car had to be aware of it by then). Definite improvement changing lanes on gradual curves too, felt more authoritative as it purposefully merged over instead of simply taking a slightly wider curve to end up in the new lane (now it waits an extra 0.25-0.5 miles). Overall I'd say lane changes seem like an improvement.
Also NoA no longer forces me to one of the rightmost lanes unnecessarily in 2 of 3 spots in one of my common drives. In one spot it used to always route me through the rightmost tunnel where you don't actually need to merge right until maybe a mile past the tunnel, and in the other it always forced me to the rightmost lane that merged with another lane. Not sure if the maps got better or the NoA logic improved.
On the downside I've had noticed many more random "phantom" braking events particularly in traffic - I didn't see it try to track the cars in nearby lanes like I've occasionally seen in past versions so I'm not sure why it's doing that.
EDIT: oh, one more thing I remember that I've never seen before - previously when coming up on another car quickly, NoA would catch up, slow down, then suggest a lane change. I don't know if it was the combination of the speed differential and having plenty of space around but with 5.15 NoA prompted me to change lanes well before it would have to slow down. It gave the usual "confirm change to faster lane" prompt even though I was already going at my current setting, while the car ahead was going maybe 5-10 mph slower. I accepted and it merged around the car without dropping a single mph. I have NoA set to the medium setting (not Mad Max).