I got this 2 years ago. My initial use was my daily commute. Every work day, I'd pack in my 15.6" laptop, my lunch (glass lunch containers), power cord, portable hard drive, mouse, note pad, pen, pencil, etc, and an extra visor. The backpack was perfect for this, and I'd recommend it to anyone as a daily commute backpack, even for school with text books.
This model features expandable storage. This is super useful when packing several days worth of clothes for a 3-4 day trip. It's surprising how much it is capable of carrying. I originally babied it because I was worried I'd deform the hard shell, but it has survived some abusively big loads. This backpack is capable of carrying 2 laptops securely. 1 in the regular pouch for 13-15.6" laptops, and the outermost pouch can stretch to hold up to 17" or 15.6" with an expanded battery pack
Heaviest load carried
: 1 X Alienware 17" gaming laptop, 1 X 15.6" Lenovo Laptops and another 15.6" Dell with an expanded battery pack, along with all the power bricks, my lunch, and my 2.5" portable hard drive. OMG that alienware was heavy!
This backpack also comes with a waist strap with a lil pouch. I used this for a few months before opting to just store my wallet in my jacket. Others have found this to be really useful, but I didn't care for it. There is also a helmet carrying strap, but I only ever used it when I needed both hands. I had a tough time with crowded streets since it made my body wider with the helmet on my side, so I eventually just took it off and carried my helmet around.
There is plenty of little pockets for small items. My favorite pocket is accessible externally at the top of the backpack. I normally store a few USB drives here for easy access, or other small items. The visor carrier is useful, but I no longer change visors due to a new helmet with integrated sun shield. Sadly I'd have to cut it out to remove it, but I can't bring myself to. The shoe holders I've used a few times, but I often opt to just carry them in a plastic bag instead.
After 2 years of daily use (my old backpack died so I use this even in the winter now), it is in remarkably good condition. All the zippers function well (as they should) and externally it looks almost new. The only tell tale sign of use is that the bottom, which used to be pointy, has lost some of it's shape and flattened out a bit from sitting on the floor with stuff in it. But anyone unfamiliar with what it looked like new would have no idea it has flattened out a bit. This is not an issue for me. I am careful not to drag it across surfaces, or otherwise cause damage from abrasive surfaces. I don't throw it around, so if you treat it with care, it will last, despite loading it with heavy stuff.
Ergonomics, safety, and aerodynamics
It can take some time to get the straps adjusted correctly to fit your body. The straps are asymmetrical due to the helmet strap on the one side. So you have to pay attention to get it to fit you correctly on both sides. Once set, you'll never have to touch it again, unless carrying at full capacity with the expanded bit maxed. Then it can be a bit tight. With it's snug fit, it doesn't move around your back while riding and is quite comfy. With really heavy loads i let the backpack sit some of the weight on the back seat (yay upright riding position!).
There are 2 high viz stripes going down either side of the Mach 5. I feel a lot safet knowing these lines light up at night from headlights.
The aero performance is impressive. If you go over bridges with big wind gusts, you will be happy to have this equipped. There are also a bunch of elastic loops to keep loose straps from flapping around.
Should you get this?
If you appreciate it's looks, and don't mind having to open up the clam shell to get at your stuff, this is a pretty fantastic motorcycle oriented backpack. It can carry more than you would expect, and will last a long time if you take care when putting it on the floor.