I have a Seek Outside Unaweep, HMG Porter, and a stripped down McHale LBP, and have used packs from ULA, SMD, Gossamer Gear, Golite, Osprey, Gregory, Mountainsmith, and Zimmerbuilt. Fit is the most important thing and is very personal, but I will say that to me, the Seek Outside is the best load hauler and an excellent pack, though can be a bit unrefined. I haven’t used the Divide, but it looks like it might be a bit more refined for us backpackers. It is a pretty big pack though, so it may not be the pack for you if you are looking at a Porter 2400.
I do like the weight and a lot of the features of the Porter, but the shoulder straps and hipbelt aren’t up to the same level as the Seek Outside.
The McHale is by far the most refined, but isn’t big enough for trips over a week (mine is 2884ci) with a bear can and heavier than my other options. When I bought it, it was going to be the last pack I would ever buy, but the need for a larger pack got me to try the Seek Outside and I really really liked it.
As far as fabrics go, I have the XPac X21RC and if you are wanting bomber, I would go with the X42 or X51. I don’t think the X21RC or the 150D Hybrid Cuben is as tough as 210d Dyneema Grid, but of course nothing is going to beat woven Dyneema, but at a cost. The XPac is waterproof though.
I have no experience with Katabatic packs, so I can’t comment on them.
If you want a large load hauler, the Seek Outside Divide in X42 (or custom X51), or the HMG Porter in Dyneema (if you feel the normal hybrid cuben isn’t tough enough for you) are hard to beat.
If you want a smaller pack, I would add in a McHale Bump which is $700 with accessories.
In the end, fit is king, so get what fits you. I might even buy a Porter on gearswap and make sure it fits before you spring for a full dyneema one if you go that route.