After reviewing many backpacks, both online and in person, Iv'e decided that I want the Osprey exos 48. Unfortunately, the only Osprey dealer in my area carries only the exos 58, and they had it only in the medium size, which I tried and felt great on my back, although the hip belt felt was a bit large (I'm slim fit). Since the 58 is too big for me, I'll be ordering the 48 online. My torso is of size 18", which by the Osprey sizing chart (attached) means small or medium. I'm reasonably sure that the small would be an even better fit for me, but is it worth taking the chance?
What's worse, a slightly too big or slightly too small backpack?