I'm not affiliated with either of these companies in any way, don't know anyone who works for them or anything like that. Just a ton of the guys I work with have stuff from both of these companies and theyre stuff is so awesome I'm jealous of it. If I didn't have a perfectly good seagull bag I'd buy one of their bags.
Skingrowsback.com Sick u-lock holster, awesome courier bag. It has reversible straps, x straps, lots of extra features for poster rolls and stuff removable breathable back pads that can be machine washed, the works. So many guys I work with have this one and it is awesome, I wish I had one.

Bogear.com.au Brisbane outdoor, also sick stuff. They make some cool footstraps for use with bmx pedals that I do have. I can't really compare but I think holdfasts might be better. They're pretty good though. Their bag is also really awesome with lots of little spots to store things and strap things to.

I am not a shill, I just know that all you kids out there love to have stuff no one else does and Im pretty sure theres not too many people in LA or New York with one of these bags. I have seen products from both these companies in daily use and they kick serious butt.
If this is somehow against posting guidelines then feel free to delete. I'm only posting this because I've been on here a while and have never heard either of these companies mentioned when people talk about messenger bags.