I use team elk. It's heavier but the scabbard is awesome. For now I use mystery ranch, but I've used the team elk without a second thought. I use the scabbard area for more storage.Looking at the Eberlestock series...
They have put out the vapor series that is lightweightIn terms of quality, the Eberlestocks are the nicest packs. They ooze craftsmanship and ruggedness, not a stray string, everything wraps up efficiently, they are just the best and I've owned countless quality brands. All that said, as noted by a number of posters, Eberlestock packs are relatively heavy, and that can be a tremendous downside depending on the application.
K4 I think is the best pack system I've used to date.I have a couple Kuiu packs that I really like. just bought the new exo K4 and will be using it in October on a Colorado elk hunt. I have wore it on a couple walks and so far like better then kuiu. It seems to fit my much better, and the pack constructions seems much better.