What do you currently use and what kind of use are you looking for?
And not knowing those answers:
1. Pros = Cons...hmm...you get what you pay for
2. I don't like those two big "breast" configurations...seems clumsy. The back would be for a jacket and water, you'd have to take it off...wish I could see it. $70
3. Allen vest looks nice, no big molded things. But it's a vest, not a pack. $80
4. Fishpond is good stuff, they last. But if you budget is up to $80 (the Allen vest) I'd go for the Blue River
instead, it's bigger yet not as bulky, and $70. I have a thing against the molded plastic, it just adds mass without much greater function. Not sure about all the pockets on the Arroyo, but most Fishponds have nice little pockets that hold tippet spools perfectly, though from the image it doesn't look like it does.
You've narrowed it down and I don't want to add more options, aside from the alternate Fishpond pack that is in your price range, because you've already learned that there are way to many options out there. You're certain to get lots of new recommendations.
Ultimately it depends on how much you want to carry and where. The Fishpond packs that say "chest or lumbar" are really, in my opinion only lumbar, or fanny packs. I wouldn't want all that hanging from my neck and on my chest.