Hi JASNY, just now responding since took yesterday off from Internet to celebrate Decoration Day.
1. When minute or hour hand is between 22 to 38 after sometimes chrono timing can be difficult to read since hand may block counters but not the entire period. I use chrono for client consulting and time in casino but for practical purposes I'm able to make a good estimate when temporarily blocked.
2. I have several scratches on top of bezel but I suspect most are due to my carelessness. Bracelet has bruises on several links when I forgot to remove watch while unpacking and moving a heavy sculpture.
3. I agree with your comment about timing events whatever you want and I repeat that the wings provide nice ergonomics when pressing the pushers.
4. I previously owned 5165 but no dato, but I much prefer the look of this Nautilus to Aquanaut and inclusion of complication is great because I would be less bothered by case wear due to regular use of 5980 as opposed to care that I would want to afford a dato.
Regardless of your choice, or if you decide to acquire several watches for celebration, enjoy your 50th.