For commuting large saddle bags can be kind of annoying IMO. A faff to pack/unpack and to remove and refit when locking up etc.
Carradice quick thingy (bagman whatever it's called) is as fast as my Ortlieb panniers.
Reinforcing struts were necessary in my case though, support felt too flimsy on their own, but in @HoKe 's case, if he can get away with only the quick attachment system and rest the bag on the existing rear rack, that would work nicely.
Carradice SQR takes about 2 seconds to put on and take off. I commute with an SQR Tour and it's awesome. Would never go back to sweaty rucksack back and no need for a rack to weigh you down on non-commuting rides.
Carradice quick thingy (bagman whatever it's called) is as fast as my Ortlieb panniers.
Reinforcing struts were necessary in my case though, support felt too flimsy on their own, but in @HoKe 's case, if he can get away with only the quick attachment system and rest the bag on the existing rear rack, that would work nicely.