shop employee and exclusive skier of pivots here:
for any binding, you want to be as close to the middle of the din range as possible, this is so that the spring can have the most movement possible, this will extend the life of the binding.
Ski bindings are also tested so that they release with a certain amount of force, for them to release as accurately as possible you want to stay away from the top two or bottom two values.
Pivots test VERY poorly at values below ~8 (meaning at below ~8 they require more force than is appropriate for the shown value).
All of this said, pivot 15 toes are indestructible, (and my personal choice).
pros of 15:
-durable
-good looking
-CAST system capability
-‘metal feel’
Cons of 15
-Heavy
-Expensive
-No vertical toe release
-almost impossible to get to test accurately below 8ish din
-only 2 points of toe contact.
Pros of 12/14:
-test reliably at 6-8 din
-cheaper
-lighter
-have a purely vertical toe release
-3rd point of contact to the toe of the boot
cons of 12/14:
-plastic feel
-less durable (start to get cut up)
-no CAST integration
-Less cool looking
All in All:
If you are planning to ski at over a 7-8 din the 15 should be fine, at 6.5 it might test well from my experience, but probably not. The 12/14 is probably ‘safer’ due to a lighter weight, a third point of contact with the toe and the vertical toe release. But I have seen old Pivot 18s that are 5-10 season old that are still in good shape.
Either is a good choice, I might recommend the 12/14 a little more for a recreation skier, but if you think you are likely to gain enough weight to ski above ~10 din, and want a binding that will be kicking around next decade, the 15 is a great choice.
Also:
older thread on same topic:
https://www.newschoolers.com/forum/amp/924665
and Dollo was skiing a pivot 12/14 in BRUSHINO, so I don’t think it’s a bad choice.