Both with the rifle's use being "all purpose" and with the range of a .308 (zero to 500+ yards), I believe the "pros" of a variable scope are readily apparent. For closer distances, being able to adjust the scope to a lower power will make target acquisition more rapid. At father distances, or close distances where accuracy is essential, being able to adjust the scope to a higher power is better.
I can't speak to the statistics on failure percentages related to fixed versus variable powered scopes. However in my (very limited) experience, scope failures have been primarily due to reticle issues. I did have one seal issue, but it was at the front objective on a fixed power scope. I've had no seal failures on any variable power scopes. In fact, all my failures were on fixed power scopes. However that may be because my fixed power scopes are not near the quality of my variable power scopes.
NRA Life Member
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"There are some ideas so preposterous that only an intellectual will believe them." - Malcolm Muggeridge