arcteryx altra vs naos?

arcteryx altra 75 vs the arcteryx naos 85
naos is bombproof but also heavier and much more expensive. i take care of my gear but i also run my stuff hard so is the extra $250 worth it... im in hawaii so holding and looking at these bags is not possible. ill be using this bag for a 5 day trip to kalalau valley on the island of kauai. its wet, rainy, salty, and ill be seeing everything from sharp lava rocks to muddy wet forests on this trip. help a isolated hiker out thanks!

How did you narrow it down to those two packs? Arcteryx stuff is expensive- may be overkill for a backpack trip.

My theory is that if you are going to be rough on your pack you can either do cheaper packs and accept that you will replace them every year or two. Or expensive and hope they last a life-time.

I have two "heavy duty" packs- an expensive Arcteryx climbing pack that regularly gets scraped on rock and a cheap Mountainsmith pack (on sale from Sierra Trading Post) that is not that comfortable (does not fit me right- bought it on the internet without trying on) but will not die (I wish it would tear apart! then I would not feel I had to use it).

I would never buy an expensive pack that I could not try on. I would instead pick the best pack from what is available to try on.

For a small fee you could ship me that Mountainsmith pack that doesn't fit you and, in return, I would GUARANTEE you would never see it again.