I like my
I like my Mini-Trekker. It is airlines carry-on legal and still holds a decent amount of equipment.
As an example, for an upcoming Aaska trip, I am carrying two cameras (10D and 30D) and four lenses (12-24mm Tokina, 17-55mm f/2.8 IS, 70-200mm f/4L IS and 300mm f/4L IS) along with a TC and the standard memory cards, batteries and filters. These all fit inside the bag - a bit tight but, they fit. I will carry a 550ex flash in the outside compartment.
The bag is made very well and if I remember, I selected this over some other brands because it was lightest in weight for its size. I don't remember which bags I compared this to.
I have looked at the Kata backpack online because it has an accessory set of wheels which might make dragging it through airports easier. However, I cannot determine from the illustrations on the Kata web site if my equipment would fit. I emailed Kata asking the question a week or so ago but, have not received a rply. I will save my money and use the Mini-Trekker for the trip.