Out of the amount of time

- Security:
There are thinner locks, Kensington is the great maker, combination locks are more secure than the old round key locks (on youtube there are rows of videos on how to, for example, with some cardboard crack the round lock in seconds).
So far as I can tell there is a plus for security.

- High quality:
with many castles of plasticizers stench of the plastic sheath of the cable is criticized. Also Kensington is not better. After months of usage it still stinks toxic. However, the lock operates cleanly and without difficulty and the rubber ring (buffer to laptop) fell far not yet on how that should be in reasonable models of the case.
But because of the bad jacketing material I say high quality neutral.

- Concept:
1. It should be portable. These are all the locks of this type. This is easier, you can together Lace. I know the old castles and there is the "rubber-cloth" firmly on the lock, can be used as not to sink into a pocket or lost, but remains always optimally positioned. What have been thinking that every time you have to firmly wrap it again now ?!

2. It is the work not interfere. I have a Thinkpad T430u, which falls into the Ultrabook category. But there is much thinner ultrabooks. Nevertheless, the castle or the piston is so thick that when the laptop is connected, no longer rests on one side of the rear foot on the table and the laptop so verruscht when to come. No more stability.
Concept: minus.

Conclusion:
The castle served its purpose, but it is no better than cheaper and also impractical in many ways. A contemporary castle must not smell toxic, the "Lashing rubber" should be firm and the pistons have a 2mm narrower piston for Ultrabooks. Hama there are locks for 15 Euro. 100% surcharge for the name have traveled extensively.

Hope I have remained objective and could help you decide.