My main travel bag is the Kata 3N1-33 bag. This bag can be worn as a traditional backpack, or by hiding one of the straps and extending the other as a sling bag. This allows for a lot of flexibility when carrying. Both casual walking with easy access to the camera gear as well as steady use as a back bag in hiking situations are possible The bag also has a waist strap for superior comfort when used as a backpack.
The backpack configuration is useful when your main purpose is to actually transport your gear, such as when getting to or from your destination, or on long hikes. Here comfort of carrying your stuff is more important than real access to your gear. Note that you can use either the left or the right strap as you sling strap, making this bag useful for both left and right-handed people alike.
The bag is split into three main compartments: a top compartment for accessories and personal items and the lower part which fits your main camera gear. Finally there is the laptop sleeve at the back that easily fits a 15 inch laptop, in my case a 15 inch MacBook Pro. Also included is a memory card pouch with a velcro back, allowing to securely attach the pouch to one of the velcro strips inside the bag and a separate rain cover which is located in one of the two small side compartments.
As I use this bag for my main travel, as it can take just about everything I would want to take along on a longer travel. For me this includes my main camera body, a Canon 5D Mk II, and three to four lenses, a flash, polarizing filters, batteries, a charger, cables, memory card reader and cleaning items…
In addition I can take my laptop with charger and an external disk, which easily fits into the laptop compartment.
Two accessories are worth mentioning: the tripod holder which allows to attach a tripod or monopod to the bag. I think this is a must have accessory I would recommend getting it with the bag.
A second accessory is a trolley which can be inserted at the back. This converts the bag into a trolley bag if you do not want to carry the bag. All straps can be hidden, and the do not get in the way or dirty when rolling the bag. It works nicely and I can recommend it if you are using the bag as a transport bag and have it loaded to the max.
I do not use the trolley that often, since I want to make the bag appear to be light and cabin luggage compatible. Putting the bag on a trolley, I think, makes the bag look heavier and probably suspicious to check in agents wanting to weigh the bag. I routinely go over weight with the bag, but since it looks very compact I hardly ever get questions on the weight.
My main complaint I have with this bag is that it is too wide. It is not so much a complaint as the problem is not Kata’s fault, but it is a result of the bag holding a 15 inch laptop and has to be wide enough to hold a computer. The laptop sleeve also adds some 2 to 3 inch of thickness to the bag.
All of this is avoidable, if you use one of the smaller cousins of the 3N1-33 bag, which either include sleeves for smaller laptops, or no laptop sleeve at all.
All in all this is a great bag, well designed and built to high quality standards. It is comfortable as a backpack, can easily be converted to a sling bag and it you have packed it so much you cannot carry it anymore you can use the trolley accessory to pull it along.