The one I posted has a mesh-type of padding on the parts that touch you, so it helps a little with the heat. You are going to be hot and sweaty in the summer, but I did not find it irritating.<br><br>
The straps hit over any sleeveless shirts I wore, so I did not have any chafing problems. I did get chafing when I borrowed my husband's (classic camelbak).<br><br>
If you get too much motion with the shoulder straps alone, you can use one of the stabilizer straps across the front, but I rarely feel the need.<br><br>
I picked that one because I'm often out for hours at a time, and I have all sorts of just in case items!<br><br>
What I found when I used a pack that is not "womens fit", is that the shoulder straps don't fit well, leading to lots of motion and chafing, and the length was too long to be comfortable. I am short and narrow-shouldered, so it makes a huge difference for me!