By the posts - Dr Zettl has a "B" and I believe he made the comment of him feeling that the other kite was "super brake heavy" and his felt like a rocket. Now that in my mind is backwards! With the adjustments on the "B" leaders - that shouldn't be. If anything, it should be the other way round!
I think he meant that a lack of long leaders on his kite made the other feel brake heavy, Wayne. At least that's the meaning I got from the statement. Anywho, what what Wayne said is correct.
The knot settings (differential) that you use will give the kite different characteristics in flight, will make one feel sluggish or speedy in comparison to the other. The only way to compare the two is to have them on exactly the same length of lines, handles and leader setup. I mean identical! Even one knot can make a very noticeable difference, and changes in the wind itself will compound that difference. However, that's what determines your own style and preferences. For team or pair flying the settings and equipment should be as close to the same as possible. For instance, the brake-heavy kite will not keep up with the other one because its top speed is reduced by that setting.
It's a learning process that lasts a lifetime. Have fun, smile, and don't forget to breathe.