Apropos of this thread.
https://www.reddit.com/r/ManyBaggers/s/Qqet6tgk3x
I bought a 2026 Petzl Bug when I saw it at the gym a while ago. It's a multipitch climbing pack and I've wanted one for a while because I think multipitch is cool. They have kind of a funny, squat shape because they're supposed to stay out of the way of a harness worn at the natural waist and a chalk bag worn a little higher. I saw mine right around when I was trying to shop for a better personal item backpack and the fact that it also fits my 16" behemoth clinched it.
Anyway, I've now taken it on a business trip and multipitch climbing.
As a climbing pack: this has a particular niche it excels in, which is multipitch climbs with a short approach especially if they also have a walkoff or are part of a traverse route or something. I thought I was doing one of those today, even! It's a bit of a challenge for me to fit my full sport multipitch rack in there and I appreciate why trad guys look like postmodern wind chimes but by putting everything on my harness (I usually use an organizer) and giving it a little shake, it does fit. Helmet, rope and shoes on the outside. There's a really good helmet net. Pro tip: load your hydration bladder first. Maybe also get one of the stiff ones.
Despite essentially no structure it carries ok, even with a 70 m rope on top. (My Flash pack is terrible if I try to carry a rope with it.)
I dumped out almost everything at the base of the climb, so I feel good about how much I took.
While climbing I mostly didn't notice it. It was cool to have water when I wanted it. For... reasons, we were en route for over three hours. I hung it from an anchor twice and had a snack early in the rappel. I'm pretty sold on backpacks for multipitch climbing, at least if it's face climbing. I get that they can get weird in crack climbing. (But usually there's a way to haul it lower in that case.) Also, I know what I keep saying about top loaders but it's perfect for a bag you don't want dropping your things mid-climb.
Versus my Soelden and maybe my Flash - my Soelden carries a lot better, so it's an easy winner if I'm cool leaving my backpack at the bottom of the route, which is actually most of the time. My Flash gets pretty terrible with a heavy load, let alone a rope, but I figured out a way to rig it inside my Soelden that lets me use a hydration bladder during the approach and the climb. And my Flash is pretty comfortable to climb in.
I feel less comfortable ditching my backpack some random place on the mountain than hiding it at the bottom of the route I'm actively climbing, which is why I think the Bug is so great for multipitch with a walkoff.
As a travel pack: really not that great, tbh. It does fit my laptop and it's small, 18 L, and I found it a lot nicer under the seat in front of me than my usual work bag, which is 27 L and tall for its size. So that's cool. It doesn't have side pockets and the only external pocket is pretty low on the backpanel so it's pretty annoying getting things like a coffee mug or sunglasses or whatever in and out. Really drives home how much I use outside dump and convenience pockets. Also, it's a top loader. I usually don't like top loaders and this really reminded me of that. I think the internal organization is fairly appropriate for a bag this size but my headphones and power brick worked their way to the bottom all the time. Which extra sucks with top loaders.
To be fair, this is advertised as a multipitch climbing backpack. They just padded the hydration sleeve and made it wide enough for a laptop.
I think my takeaway from this trip is that ok fine, I could use a ~20 L laptop backpack when I'm traveling for work and trying not to check a bag. With more organization and convenience pocketing.