I have the smaller one. The pockets are actually quite useful the way they are configured if you like having stuff in places that you can quickly put your hand to. For example, the outer side zip pockets have contained items such as small first-aid kit, the "waterproof" cover and pocketknife/stone. The front has housed my reflective bandolier and back-up lights and reflective anklets for randonneuring. The top pocket houses important documents (passport, wallet, brevet card). And the inside has space for cameras and other stuff as you sugget. I don't know about the bigger bag, but the small one has a stout carry handle, and I've never used the shoulder strap it came with.
The one significant issue I have with Topeak and Tioga and other various handlebar bags I've used is the plastic formers inside are not overly strong so they tend to sag around the mount if the bag is overloaded with weighty gear. Perhaps it's a design element suggesting that when the bag sags, it's overloaded and may affect your bike's handling.