"Dan, have you used your Catalyst yet? How's the fabric?"
It's still creeping along in the postal system but it should be here this week. I hope to get it out for a quick weekender soon, but it won't be fully utilized until my big trip in early May (~12 days).
"Dan, are you worried about the pockets and straps of the Catalyst getting caught whilst rafting?"
I'm not worried about the straps catching. I'll just keep them reasonably snugged up. Drybag hauler stylepacks (ie. ULA Epic) have straps everywhere and people use those just fine. I never had any safety concerns with my NRS Paragon (straps everywhere) last summer.
"Does the load carry ok with the packraft underneath the Catalyst?"
The bottom packraft straps are really an 'overflow' tool for a raft, paddle, snowshoes, CCF pad or whatever on long/bulky trips. I'll rarely use them. I prefer to store my packrafts inside the pack. I typically carry my wife's too, so I store two side by side in the pack bottom via Roman Dial's "packraft fold". It protects them better and rafts are not something I pull out frequently so it's not annoying - especially considering I'm probably digging out paddling clothes, PFD, inflation bag etc anyways. I presume the load will carry better with the rafts inside.
I suppose there's the argument that putting the raft outside avoids getting water in one's pack. That would probably be more of consideration if I was frequently transitioning from padding to hiking, but that's not very typical for me. When my raft comes out, it's likely coming out for the only time that day, so it's not a big deal to flip it over and let the water drip off for a couple minutes after. By the time it's all folded up there's not much water left.
The ULA Catalyst is spec'd at 48oz, but with the optional trinkets removed (-4oz) and in cuben hybrid (-5oz), it's going to come in around 39oz. A 4400 porter is 31oz, but by the time you add hipbelt pockets (+2oz?) and the rear 'Stuff' pocket (+4.2oz) you're at 37.5oz and you're still missing side pockets which I value. The Catalyst also delivers a proper framesheet (which prevents it from turning into a sausage when it's packed full), a more robust hipbelt, back padding, and ULA made mine with green cuben hybrid fabric instead of white.