A lot of folks have discussed their benefits, so to dig into the compromises vs the EL SV/FP 12's, based on my experience with them thus far:
1) Eye placement. Out of the box, NL 12's are more difficult than other Swarovski's to just "walk into the image" without the occassional blackout or...
Just got the NL 12's.
High quality glass, no doubt.
However, I'm not convinced they are a big enough upgrade from the EL SV 12's. There are compromises that jump out at me. Time will tell.
For mostly wildlife photos, the Nikon P1000 (or whatever the newest one is).
For mix of photos and videos, the Sony RX10 IV.
Save the big, heavy lenses for the professionals.
Hoyt Carbon Spyder and Carbon Element 3G for backup
But my family shoots Matthew’s and when I upgrade I will buy a Matthew’s to join that gentleman’s club.