Guess I'll wait to invest since the market is shifting so much. For personal reference, my take as it currently stands:
Grip is most expensive and most popular.
Ranger is a popular cheaper alternative.
Ergo2 is the up-and-comer peoples champ.
Simian has a built-in stool.
Gateway is a classic low-cost option.
Salient has reports of quality issues.
Much anticipation for upcoming Prodigy backpack, Lat64 backpack, and new HyzerBomb bag.