I received 2018.24.1 last week, and I gave it a workout on my usual torture courses. It seems to be essentially the same as 2018.21.9 in road performance. The vehicle under AP still pulls into on-ramps, and wrong-side-of-the-road AP still works.
The AP prompt delays averaged 49 seconds with a standard deviation of 8 seconds. Perhaps two seconds of the standard deviation I attribute to not noticing the prompt when it first appeared, but the variation in prompt times is still unexpectedly large.
I want to especially call attention to the impressive dedication Tesla gave to Barrett Riley in the Release Notes for the new Speed Limit Mode. I believe this is unprecedented in the auto industry to dedicate a safety feature to a person who died in a vehicle accident. Tesla is truly a unique car manufacturer.