It sounds like you are talking about led. There are several advantages to leds. They last much longer than anything else and they use less power. They are low profile so it doesnt look like you have the full red and blue lightbar on top of your car. It looks more like a ski rack from the front. The downside is they are more expensive than most other lightbars. As far as effectiveness, i dont know of any studies but my dept is slowly switching over to using some leds along with rotators. It becomes a matter of cost when you get to large agencies so whatever can be had for the cheapest is most likely what will be bought.
My wife left me alone with a case of Corona, a bag of limes and the cat. Beer is gone. What will I do with the extra limes and the cat?