The pop up's ability to "pop down" is the big advantage for me for whitetail hunting. If I never left the ground, and always carried a ton of gear, I'd definitely go with any one of dozens of the stationary frame packs available.
Also, you can use any bag with pretty much any frame if you spend a couple bucks and buy a speedy stitcher. Some may require a little more work than others, but it's not rocket science. I love the pop up frame, and now have three different bags that mate up to it with just a couple hours of work.