My new rig has a limo tint on the front and rear windows, and I love it.
Not only for security because no one can see what's inside my car, but this summer I've noticed they keep the car much cooler during the day because the sun can't heat any air inside the car. I can also drive around without sunglasses on in the sun unless it's shining right into my face.

The negative is that at night it can be difficult to see when it is really dark, but I've gotten used to it.