From my own experience with rifle scopes, binoculars, and spotting scopes,
Nikon was poor. Poor repair work.They charged $10 or $20 for 3 drops of superglue; the thing broke after 5 minutes.
Leica was slow. Slow, but good work.
Vortex was perfect, they replaced a spotting scope for me.
Leupold was perfect, they repaired an older rifle scope and replaced a pair of binoculars.
Swarovski was perfect, they rebuilt a pair of binoculars.