I have ran the Initial Ascent 4k system for the past 3 seasons and I absolutely love it. I had a MR Metcalf previously and hated it so I sold it and picked up the IA instead. I've packed out 6 deer and 5 elk with it in that time frame and it's performed flawlessly. 2 of those deer were packed out in one trip by myself with bone in and all my gear for about 3 miles and yes it was heavy but it was very comfortable for the weight I had. I've also used it for 3-4 day backcountry trips and had just enough space in it to carry my gear in and out but probably would want to bump up a size bag for anything longer. That being said, I don't have the lightest, most packable gear items so I'm sure if you have more of the nicer, expensive gear items like tents or down sleeping bags that are more compact you'd be able to use it more for a 5-7 day trips.
Also, the hooks on the side of the frame work awesome for hanging whole quarters on. I used it this last season to carry two elk hind quarters for about 3/4-1 mile downhill and it actually didn't feel any heavier than the times I packed out my full deer in one trip, just wasn't as far of a hike. I think his name is Hollywood Dave?, but he uses the hooks for this purpose all the time.
