I got them both to try and see which one worked best for me for weekend backpacking and climbing. I took both on a 4 mile hike with about 40 pounds of gear and the Prophet won for several reasons. First and foremost, the back panel feels like it was made just for my back. It was so comfortable! Adjusting the fit/suspension is really quick and easy. Halfway into the hike (and the other trips I've taken it on), I forgot just how much weight I was carrying because it felt like nothing. It's a very streamlined pack--everything you need and nothing that you don't. I only have two small gripes--I wish there was a little more padding in the hip belt--even wearing it with layers, the I wished the belt had some better padding--the shoulder straps had similar padding levels, but those didn't bother me at all. I also wish the fabric on the bottom of the pack was more substantial--it shows wear pretty easily. Scrambling over rocks on a climbing trip resulted in noticeable scratches and nicks in the fabric.
I tried the South Col as well because it's billed as being very similar to the Prophet. But I didn't like the back panel as well, the padding dug into my mid-back in an odd and uncomfortable way. It was also more finicky to adjust--I never could get it to feel just right. I liked the fully padded hip belt and the removable top that you could use as a small day pack, and the flat closure system when the removable top is off, but I found it bizarre that it lacked side panel water bottle pockets.
I really wanted to like the South Col because it's got a lot of nice bells and whistles, but the Prophet fit me better. Were it not for the bottom panel fabric and the thinner hip belt, I would give it five stars.