So, I have a size 5 Brain Cell and am really quite taken with it: I use it quite a lot around as a stand-alone laptop case. (I've found that you can cram a surprisingly large amount of stuff into that exterior mesh pocket, as long as you don't try to snap it up afterwards.)
When I'm going to and from work I've been loading my Brain Cell into an old daypack from REI. It's really quite a nice bag but I'm finding it a little ackward with the Brain Cell: it zips down the sides to open, at which point the Brain Cell tends to fall out. Also, the various pockets inside the back of the main compartment tend to interfere with the Brain Cell.
Now, I'm considering the Smart Alec. (The Brain Bag seems like a nice bag but just seems like overkill when heading to work.
But my worry is where I'll put everything with no exterior pockets. Where does my water bottle go? An umbrella? My sunglasses? I also have a large open pocket in my current bag, which isn't so good for keeping things dry, but provides a handy place to stash my purse and my knitting where it's easy to get to without opening the main backpack. If I carry it onto the airplane, where do I stick my boarding pass?
How big are the pockets on the inside back of the bag? Could some of the stuff go in there?
I'm torn: the Brain Bag seems WAY too big, but the sleekness of the Smart Alec seems terribly impractical.