Well, I've finally got everything installed and I'm not quite satisfied.

The Klickfix adapter seems quite solid and handles the speed bumps without problems and the Freepack Meta II backpack is well built and has lots of useful features. However, I'm having some problems with the brake/shifter cables and steering.

The first problem is when the luggage truss is empty. Brake and shifter cables get caught in it when steering, making it dangerous. With the truss came a velcro strap to avoid this. However, With the strap fitted I can't lift the handlebars high enough to fold the bike, so I have to remove it everytime, and put it on again after unfolding. I think I can come up with a better solution, so this is not such a big problem.

The second problem is that the backpack is really hard to attach, as you have to tilt it backwards for it to "click" in the luggage truss. When tilting it backwards it strikes the handlebar post so it's really difficult to attach without folding the stem. Moreover, when attached, the brake levers hit the top of the backpack when steering, limiting the steering ability (and I'm worried about damaging the backpack too). This is not a big problem when riding in most conditions as it occurs mostly in tight, low speed maneuvers, but I don't like it and I'm worried it will damage the backpack over time. The only solution I've found is to raise the handlebars at their maximum position, where they barely clear the backpack. However, this position is really uncomfortable, especially when climbing, which is something I have to do on my daily commute.