I’ve climbed in both.
Acrux-Multi day/long days your feet will be happy in a double boot for sure. It’s a low volume double boot so it doesn’t feel cumbersome.They climb great, super warm and are very comfortable to walk in. For durability...some of the first boots made have a known issue as far as the front rand delaminating. Called Arcteryx within 30 minutes I had a shipping label via email and received a brand new pair of boots within 3 days. So buy one cry once, dead bird customer service is second to none, If that is also important too you when dropping a lot of pesos for some boots. from my experience La Sportiva has “good” customer service, but Arc’teryx is spot on.
NEPALS- good at nothing, will work for anything. Durability ...those boots are built like tanks, thick leather, burly rand. With out a doubt they will be more durable than ACRUX boots.
I have used the procline ski boot aswell, it’s my opinion that sportiva and arcteryx fit interchangeable.
Just my opinion, try both of them, go in the afternoon get your socks you climb with and kick around and find the boot that’s right for you, short answer is both are good.
Hope that helps.