Bags are almost always inconvenient, and even when they are convenient they never fit enough stuff, so I prefer backpacks. Backpacks have just one downside: a slightly awkward design or the wrong outfit, and suddenly you look like a schoolkid.
For myself, I found the perfect option: the National Geographic NG A5250 bag/backpack. It is as stylish as a bag and as practical as a backpack.
Cons:
- after 4-5 months, some paint wore off the zipper pulls
- the straps are not especially ergonomic when worn as a backpack
- without a laptop inside, it does not hold its shape well
Pros:
- build quality and materials
- despite its compact size, it is quite spacious
- convenient backpack-to-bag transformation