- Synchronizing clutch and brake
- Eccentric cap
- Flicking minutes
- Self adjusting hammers
- Le confort ("user-friendliness")
If you are not sure you got all the mentioned details, I can recommend Ron DeCorte´s article (watch around, Nr. 010).
Another reason why we don´t see that many around/here, could be that quite a few people seriously interested have to safe longer than ever before ... ;-)
If you like it, go for it
Oliver

Enjoy your watch, fully.
After all, if you got it, it is because you love bit, and that is the most important.
To answer your question, the 5070 needed time to win the hearts of the collectors.
It may be the same for the 5070, even if I find itt less desirable than the 5070, but this is just my very personal opinion, nothing else.
Best,
Nicolas
I passed on the 5170 because of the pulsometer, which indicates that the 5170 is a medical doctor's watch vs. the 5070's tachy for gentleman race car drivers.
the 5960 doesnt have any kind of scale, which I think is a more contemporary design because we have digital heart rate monitors and speedometers these days

what is important is what you like.
The 5070 was a strong piece, with a lot of character, in comparison the 5170 seems more "quiet". But if you look at all Patek chronographs in Patek Philippe history, then you see a nice return to the classical Chronograph form. And the caliber is a beautiful step forward.
If you like it, if you feel comfortable with it, why trading it?
cheers
Francois