I've had a Pop Up 28 for couple of years and have been very happy with it's abilities. With it's slightly larger size, and frame enhancement, the 38 should be a terrific pack.
I just received a Sawtooth 45 yesterday. I have a Day Lid and pack cover coming today. I was wanting something just a bit larger, but on the Guide Lite MT frame. I really like the idea of the 270* zipper for access and the overall layout of the pack. The sale price I got it for was the whip cream and cherry. I have plenty of time to work the bugs and dial it in before Oct.
