Joining this thread incredibly late, but I wanted to chime in and give support to Property Of, in case anyone is using this to inform a purchasing decision. I have their Arnald Work Bag and their Carter Duffle. Both have been fantastic bags for me. I use the Arnald for work and the Carter when I'm on my bike. I've used SBL, Filson, Mitchell, Billykirk, Will, etc. For my money, the only one that comes close is Billykirk. Their lack of pockets, though, is incredibly frustrating. External slip pockets are so useful; in the airport, getting the mail, or, if you're the proverbial absent-minded prof like me, constantly forgetting to put that last paperback or essay in your bag, a newspaper pocket is so useful. The Property Of bags are loaded with useful pockets, both inside and out, and it really feels like they privileged practicality in their designs. One of the best features of the bags, for me, especially in the Arnald, is the weight distribution. When I load the bag down, it's still very comfortable to carry. It feels like the weight is distributed very evenly throughout, and the snap handle is really comfortable, even on campus-wide walks.
In terms of comparing their Tommy Trip Bag to a Filson, it's tough. The Filson bags I've used have always seemed a little clunky. I know there's a huge Filson following on SF, and I respect many of the reasons people choose Filson. But, for me, they just don't feel easy to use. So I'd say the Property Of is a winner. But, of course, all of this is completely subjective. I just offer my humble two cents here.