I found this pack after much research and was really driven this direction after reading Phillip Werner's review of it on SectionHiker. Here's my final comment on th Kalais XT from that forum:
For what it’s worth, I’ve also found the side pockets to be exceptionally well-suited for carrying morrels home when I find them trailside. I’ve put 60-70mi, on the pack since receiving it early this year and have really enjoyed it. We frequently carry way too much extra water weight here in the Central OR high desert, and I also often carry some gear for one of my kids. This pack carries the additional weight splendidly (though my knees don’t appreciate it!).
The Kalais XT pack has been a joy to carry both sub-alpine and in the desert and is very versatile for such a lightweight pack. Wonderfully adjustable fit (if you purchase it in the right size ranges–which Matt is very helpful in determining), and a simple, great layout in every respect. The X-Pac shows absolutely no wear at all after rubbing on numerous snags and brush throughout my off-trail wanders.
Matt was very punctual and helpful both in his responses and suggestions. I think this pack will be one for the very long haul.
I took an Osprey Stratos on my section hike of the Appalachian Trail last year and weighed in at 39.8 lbs. fully loaded, pack and all. The pack did well considering the weight I was carrying, but I wanted to shed weight in various areas, including pack, without sacrificing comfort and load carrying ability so I’d be able to enjoy the hike even more. I also wanted something a little more water resistant.
This pack is about 10oz lighter than my Osprey and and doesn’t sacrifice in the comfort/durability area as some of the UL packs do. It was between this one and the Hyperlite Southwest 3400. I chose this pack after a lot of analysis, even though it’s a little heavier because the features like the back padding and big side pockets. I was also considering the Zpacks Arc Blast and Arc Haul, but they did not seem as durable or like they’d be as comfortable with a heavier load.
I took it out with about 20lbs of gear and it carried very well. It’ll have about 8-10 more lbs loaded on my section hike once my clothing and some miscellaneous stuff is added, but I suspect it will carry well given the feel of it with a 20lb load. The roll down top and sides can be secured and tightened to obtain a really secure and compact fit that hugs the body well. The roll down top is massive...could easily put almost double the gear I’ll be carrying if I filled it up. Not that I want to do that, but I wanted a pack that had the extra capacity, if needed, as I anticipate taking my son with me in the future and will need the ability to carry some of his supplies.
The pack took a little while to adjust and get dialed in. The instructions definitely helped with that. If ordering, I’d advise doing so about a month before your hike. With these packs being custom made to order, you’ll need to build in 1-2 weeks from time of order to receiving the pack and having enough time to get it dialed in and take out on a few hikes prior.