Some techniques, like Buddhist mediation techniques – Vipassana, long silent meditation courses, require several hours of practice for long periods of time.
The advantage that The Art of Living techniques have, from what I have heard from people, is that it is not as time-consuming. You get results very quickly, because you are changing the rhythm of the breath. The technique is highly suitable for people who are very busy in their lives. It is like a power nap. It quickly gives you the experience of a deep meditation.
Even TM brings you that inner calm and peace. People who have done TM also, find it even more beneficial when they do Sudarshan Kriya and the breathing techniques. They find it very complementary to their practice, and it helps them go deeper in their meditation.
In The Art of Living techniques, there is not much effort involved. It suits the modern day lifestyle. Some yogic practices need a much disciplined lifestyle; you have to wake up and meditate at 5 in the morning, have proper food (there is a whole guideline about food, rest and meditation time). The Art of Living technique has very few restrictions, making it easier for people with busy life-styles in urban cities. They also find it easy to practice them.