ElkWhisperer, I'd have no problems buying an EXO, SG, or Kifaru used. NONE. Problem is, you don't see any of the three used much except the Kifaru 26 inch frames. If that's the height you need, then you will find one used in the next week or so. If not, you could wait a long time. Well, elk season is coming quick. So, I'd base my decision on delivery times of the new packs versus finding the used ones. And, don't believe the BS on the front page about Kifaru owners being unsatisfied. They have and still do sell exponentially more packs than either of the other two. There is simply a bunch more Kifaru's floating around then the other two at this point. I suspect it will always be that way.
Anyways, I considered the same three when I bought my Kifaru. I used a couple determining factors to make my decision final. First was all the rave reviews of Kifaru. Plus, there is guy on here called Kotahunter. He is a gear junkie and tries all the new stuff. He simply said he preferred the Kifaru due to the hip belt. So, I keyed in on searching for reviews of hip belts from all three and, found out quite a few other gear junkies that had tried all three, shared his opinion. Second factor was the wait times the others had in comparison to Kifaru, that led me to my Kifaru. I'm so pleased it worked out that way. I chose a new 24 inch aluminum stay, hunter frame because I couldn't find a used one.
Sorry I got so long winded but, I'm not the authority on this stuff. I just know what works for me. However, there are lots of people here that have owned all three. And, while most seem to prefer the Kifaru,, not all do. So, you got sort through all the favoritism and take the plunge. If you are unhappy or, still wandering after hunting season, you will be able to sell any of the three for almost full cost and try again. God Bless