Just received it today. While I obviously haven't had it on the trail yet, I've been in this game long enough to know this is a sweet pack.
-A few things immediately stand out:
*Hip belt adjustments are top notch. Coming from years of going frameless with a Jam2, MYOG packs, a GG Vapor Trail before that, and external frames back in the day, (not to mention countless packs fondled throughout the years), it's the best belt I've tried on to-date. The two adjustment straps on each side really allow you to form fit it.
*The fact that a Bearvault 500 fits horizontally and snugly (but not too tight) anywhere in the upper 60% of the pack also sold me.
*Generous side pockets. I've always been bothered by the stretchy pockets on just about every pack I've owned, forcing you to fight to get a bottle in or out, especially if the pack is full to capacity. I think updating the pockets on the new Catalysts from mesh to nylon was a wise choice as well. All my stretchy mesh pockets had holes quickly.
...nothing else to say, as enough has already been said on this pack.
On a side note:
While Brian Frankle may have created ULA (I know nothing about him other than that), Chris was great to order from and seems to be running a tight ship. I sent him at least 5 messages prior to ordering this pack asking about custom fabrics, color options, other ULA packs, etc. I don't think it ever took him more than half a day to respond. I ordered on Tuesday night and the pack was in my hands on Friday afternoon. What more could you ask for?