I have no AP1 experience but I am very impressed with AP2 so far for the past 3,000 miles (mostly freeways).
1) Avoiding rear ending with a car in front most of the times. I had to brake on my own may be twice when I thought the system wouldn't brake timely.
By contrast, AP1 had quite a few of reports:
40 mph rear ended accident at Lebec, CA
Another driver says Tesla’s autopilot failed to brake; Tesla says otherwise
Rear ended a van in Switzerland
China First Autopilot Crash: rear ended a disabled car:
'Self-driving' in spotlight again as China sees first Tesla autopilot crash
Fatal China crash into street sweeper:
2) Excellent merging. I purposefully moved to right or left side when I see a merge and it has been flawless.
AP1 on the other hand, crashes into concrete median during a traffic merge:
My car hit a barrier while I was on autopilot.. • r/teslamotors
3) Absolutely no truck lust so far. AP2 has no affinity toward a truck when passing it.
In contrast, there have been many reports of AP1's tendency to drift toward big trucks
4) Superior lane keeping even in construction zones with confusing lane markings.
AP1 drifted and hit traffic ones in the clip below when it detected missing lane markings (yellow and white markings are covered up by newly constructed white concrete)
In my opinion, AP1 is superior in its smoothness.
AP1 may be so smooth which could lead to fatal Florida accident and fatal China street sweeper collision.
In summary, I prefer AP2 for its safety rather than AP1's smoothness and I think AP2 is heading toward the right direction.