I skimmed the thread, sorry if you have already made your decision OP, but as to your original question I think this is the best answer I saw.I guess it depends on what a person considers versatile. Kifaru offerd more bags and more pockets and pouches to add on. Some see this as a plus, I personally don't and and cant stand having pockets and pouched hanging from pals webbing. Now my SG is versatile in the sense that I can throw a couple items in it and compress it down for a summer day hike and it is not floppy or strappy and I can get in it without undoing a bunch of buckles. I can laod it with a weeks worth of gear, drop camp and be right back to a sleek daypack very easily and quickly and at anytime in between I can separate the bag from the frame and haul some meat. For me the SG does everything I need while still staying very functional and sleek.
Kifaru and SG are both very versatile, but in different ways. I ended up staying with SG and wouldn't have it any other way, for how *I* like to use my pack its the best option by far. I love how my 6900 feels like a legit 3000ci pack and a legit 7000ci pack all in one.
We all love gear so I look for an excuse to buy a smaller SG to put on the frame all the time, and I still can't even flirt with the idea, as the large packs work so well when compressed.
All that being said Kifarus are awesome and very versatile, but not as good for how I define the term for my uses.