In the bumpershoot thread, dorayme asked for a comparison review of the LS and the MCB. I need to organize my thoughts to do a proper review, but off the top of my head, here goes! The LS is the TB bag that I use the most, since I carry it every day instead of a purse. Right now I have two Little Swifts: a Kiwi for summer, and the Ultrasuede Cacao for winter. (Though I'm checking daily in hopes that an Azalea LS will be listed as a pre-order: Azalea for spring, and maybe some day there will be a Cayenne-like burnt orange for fall!)
Last June, when the FoJ organizer pouch was on offer, I bought a Crimson MCB just to get the FoJ! But to my surprise, since I didn't think I'd like the vertical orientation of the Café bags much, I took an instant and passionate liking to the MCB. I don't carry it as often at the LS, and it's not the bag I would take to the grocery or post office or bank for routine daily errands. I like the quick access to contents that the flap-less LS offers. (Note: I live in a rural area, so these errands are done in my car, not on foot, on a bike, or via mass transit. That might make a difference as to what bag I chose to carry.)
What I use the MCB for is my iPad bag. I made a felt sleeve for my iPad, and the MCB is the perfect size to carry that, along with an Apple wireless keyboard, and a foldable iPad stand. I put an Eco-Stylus that I got off Etsy in one of the pen pockets, and attached a small Crimson organizer pouch inside the zipper pocket to hold a smaller stylus and a cleaning cloth. Then I simply transfer all the purse things I want to carry from my LS to the MCB, using the FoJ organizer pouch for my toiletries. There is plenty of room for all of it, including a thermal mug; and I find that the Standard Strap is fine with the load. I use my Crimson Key Strap to attach my house/car keys. So I'm being "matchy-matchy" dorayme with the small Crimson OP and my key strap and my Crimson MCB!
Note one "hack" I've made is to use a Timbuk2 cell phone pouch that slides up and down the strap. Yes, there's a pocket inside the MCB for a cell phone, or I could carry it in a small Organizer Pouch attached to one of the many o-rings in the MCB. (I love how many o-rings it's got.) But whether it's me or my anemic phone, I cannot hear it ringing if it's inside the bag, so that's why I keep it on the strap.
So I love both bags, though I use them for slightly different purposes. To show you how much I like the cafe bag concept, I now have an LCB on pre-order, in Azalea/Sapphire. I plan to use it to carry my 11-inch Macbook Air, since that is too tall to fit inside the MCB.