Honestly it depends. Some D-Locks can be snipped by the same size bolt croppers that are used on Cable locks, but only really the cheap low-end D locks, whose only real benefit is appearance, but in reality they would go just as easily when attacked, just due to quality of material. No tool will make as much noise as the alarm on that cable lock. It's both, like I said before, there's an internal cable around the main steel braided cable and when that is snipped it sets the alarm off. But also it comes with a motion sensor in the head unit, detects movements and strikes and alarms accordingly (Which gives additional protection to the rest of your bike.) You're smart with the thinking, using D-Locks for their appearance however a well seasoned thief will attempt anything and would already know that some D-Locks are made of cheese. It's like of like those "armoured" cable locks, that look bulky but in reality are very weak, it just takes the right thief. Appearance deterrent is only buying you time until a more intelligent thief comes along IMO, and personally I think appearance deterrents are something that you should not rely on. Atleast with the cable-lock, its appearance, would sit happily within a cafe stop or on use on a front wheel, but its actual abilities would be able to rank it to much greater use, providing more security than a D-lock, because SHOULD a thief stroll up to your bike with enough tools to slice through any quality D-Lock, no matter what tools he uses he can't defeat the alarmed cable lock, because it'd certainly alert you, and certainly spook the thief. All-in-All, that cable lock is an incredibly Potent lock for its size, weight and flexibility.