I have one and a couple others. What I like about it is it has several outputs and adjustable focus. You can't get that anywhere else for the price. You can adjust the beam down tight for long range engagements or open it up for close work. You can also turn the power down to where it is usable in close quarters.
I also have Streamlight IR SuperTac. It is a lot of illuminator for the money as well, and more powerful than the armasight, but not adjustable in any way. Armasight is supposed to be releasing an illuminator that is adjustable but twice the power.
I feel like both are worth the money. Be aware that armasight has two models and one is not adjustable (I think, just from researching when I was buying illuminators)
I'm currently gathering up several illuminators of all makes and models to do a side by side test to find out what the strong and week points of each are.