TLDR/BLUF: Build Quality is top-notch, seriously none better. Zippers, stitching, pull tabs, straps... all very solid construction. I own a lot a bags, from a lot of companies, and this one is at the top now.
You are essentially getting 3 products in one, with multiple configurations. As a full setup, I was able to get 6 days worth of clothing/gear (no hydro) reasonably packed into a setup that was manageable to carry (photo). If you go the Warhammer/Little Brother route you might get more room and the Warhammer wings are a little more functional than the Skycrane saddlebags. I wish they didn't come to a full taper, but not a dealbreaker.
What I really appreciate about this bag are the small details, i.e. the hooks at the end of the pulls to attach to the J-79 so the LB doesn't unzip from the J-79.
Only reason for the star knockdown is the color of the main J-79 (main bag) and the little brother are eevvvver so slightly off; and the previously mentioned saddlebag taper.
Its comfortable and relatively easy to adjust the harness to the correct setting (J-79). Compression straps get the load to a decently compact setup. Pocket and MOLLE placement/design are solid, though I don't think I would use the MOLLE along the saddlebags as it would create a very wide setup.
Looking forward to testing more setups in an extended 4 day loadout, I think that is where this bag would really make its mark.
Bona fides for those that care about that sort of thing: 14 years Army, 2 years conservation LEO, 6 years hunter, 20 years hiker.