Thought I'd post this here, not sure if it's the right forum but I'm sure it will get moved if it's not!
I'll be comparing this bag to Chrome's Kremlin since it's the other bag that I used for a long time. I can't post side by side pics since I don't have the Kremlin anymore, sorry! I do have one pic next to Timbuk2's largest bag though.
First pic is the bag next to a milk crate for reference. Pretty straightforward...
Followed by a picture of a lanky guy wearing the bag
Next up is a picture of what's underneath the main flap, lifted up to expose the inside pockets and their velcro.......lid?
When you lift up the small flap (lid?) inside you can see the main inside storage pockets. They're pretty deep and I find them pretty functional. I carry 2 tubes, 2 tire levers, a mini-pump, a 15 mil wrench, a park allen key set, a trisocket (for fenders), my wallet, a spare blackberry battery, a spare roll sleeve, and a small notepad. It all fits very nicely, and doesn't get too bulky. There's also a key ring, a pen pocket and a zippered pocket which is nice. I'm not sure why the pump and wrench are sticking out the top of the pocket in this picture because the pockets are way deep enough for them to fit. In fact now that I think about it, everything is still in the pockets in these pictures and they barely look full at all.
Immediately opposite these pockets is another large flat storage pocket on the inside of the main pouch. It's the full length and height of the main inside pocket so there's lots of storage space. It also has a velcro closure which is nice. I usually use this pocket for small or flat items such as manifests, small envelopes that you don't want flying out of your bag, maybe my little toque and gloves when I get too warm in winter. I don't usually put anything bulky in this pocket for a couple reasons. It's attached directly to the same wall as the main storage pockets so combined with the weight of your tools/wallet/whatever it can kind of weigh the front of the bag open/down which I find kind of akward. Also, the more you put into this pouch the more it starts to infringe on the space in your main pocket.
So next up are pictures of the main storage section of the bag. Here's where the big differences start. When I used the Kremlin in the past, I found that the bag's main pocket was shaped sort of like an envelope or pouch. (2 flat peices attached at the bottom and sides) I found that when you started putting anything that wasn't a flat envelope into the Kremlin, it would become really akward. How do you fit something 3 dimentional with 4 sides into something that is basically flat and only has 2 sides? The Berlin's main pouch is shaped more like a giant rectangle. This is great for large packages and boxes. Way easier to use and fill. To illustrate what I mean better.... When you put a large file box into the Kremlin I found you had to stand it up to make it fit in the bag which is really akward. The box will sort of see-saw back and forth on your back and really **** your center of gravity on the bike. What's the difference between the bags? You can lay a file box down in the main pouch of the Berlin and still have room for more trips. The biggest benefit of this is that the box will sit on your back in the exact same way as the bag. It may be hard to tell from the pictures, but this bag is massive.
This is also where the differences in the bags main strap system comes in.
Some visualization work ahead.
Think of the Kremlin as an evelope. One seam running around the bottom and two sides with an opening at the top. With this design the straps have to attach to the side seams which can cause the bag to wrap around your body when the straps are pulled tight. Trying to put a box, a three dimentional item, into an envelope only causes the top to flop open and the sides to pull and bunch causing you to loosen the straps to make the bag more comfortable to wear, potentially make it less comfortable and less stable while riding. Plus you essentially lose space in the bag since you'll never be able to fit a box into the very bottom of an envelope or the corners which makes you less effective at carring large amounts of trips.
Now think of the Berlin as a box. It's designed as an expandable rectangle instead of a two dimentional envelope. Think of a suitcase with an expandable main or pocket compartment. The Berlin has straps attached to the outside front and back seams that can help you maintain the shape you want/need your rectangle to be i.e. loose straps = full, open rectangle, tight straps = smaller, contained compartment. In addition to the actual shape of the bag compartment being more logical as a three dimentional shape and it's ability to expand and contract as per your needs, the sholder straps are NOT sewn into the comparment seams. The sholder straps are attached, essentially, on the back of the bag. The length of the bag is 26 inches end to end across your back, picture the straps attached 3 inches in on either side, leaving 20 inches of flat space where your back fits. Basically, the main compartment of the Berlin extends slightly past where your shoulder strap is. This gives you an advantage since no matter how full your bag is, your straps are never contorted with the weight. The straps can still be worn tight, holding the back of the bag flush against your back while the compartment expands as needed to fit whatever crazy **** you've got stuffed in there.
To deal with hefty objects Chrome has also added concealable (coooool) and adjustable second shoulder strap. It attaches right next to your buckle directly opposite your (still useless) waist strap. This is awesome, I can't even explain. Remember that client that gave you a full file box that was only going a couple blocks, and then you got a couple rush trips, and then more and more rush trips and you carried that ****ing box around for an hour and by the time you were done your shoulder was killllllling? Not so much anymore. This second strap makes your bag feel more like a backpack and alleviates some of the load off your main shoulder. I love this strap.