I wanted one as small as possible for daily transport. First impression, it seemed small, and the PC goes ALL just inside. I have a Lenovo IdeaPad Z510 for the info and it's perfect!
At the back we can store paper, magazine, or other document, closed with a scratch.
Up front, closed by scratch, too, we can put the Laptop charger. Personally I saw people complaining because nothing was known to, I do not agree, I knew put:
The Sector charger
Wireless Mouse
Mobile Phone Charger
Xbox 360 Controller
The wireless receiver of the handle
A small USB hub
An External Hard Drive
Seriously, everything goes! Although it is normal that on and it makes a big bump before and it does not make great aesthetic but at least we know put all that! Although I avoid as useless to have it all together, and then after it weighs, but I want to clarify.
Well, basically I'm happy, I often like like a suitcase and it's perfect! The strap is also quite comfortable even if I use it less often.
In short, Mobile PC 15.6 "? You want something compact, go for it!