Yes I use it, it works, no virus found.
You install it, sets your geolocation quickly and easily, and... That's all.
By day, your screen will have a ~6400K (bleuish) color temperature (but you can change the "day" color temperature to something else if you want), which is more or less the default you may already use.
And when the sunset begins, you'll notice a slight change in the colors of your screen, the colors becoming warmer and warmer. Depending on the settings you choose, the transition duration will be either 20s or 60m (I chose the latter).
Once the night begins, the final color temperature will be ~3400K (again, you can change it), where you'll find your screen colors a lot more "orange", warmer.
And usually, by night, you use lamps, halogens or others to provide you surrounding light. These lamps are a warmer temperature than the light emitted by the sky (almost everybody here knows the concept of global illumination :p)
As a result, by night, your eyes won't suffer from looking at a blue glowing screen, because the screen will be the same color temperature as your environment. And I can swear it's really, REALLY nice.
It's like taking a warm bath in the evening when you're exhausted, instead of a cold shower. It's... just what your body really needs.
I'm a bit disappointed no one commented on this thread, because I really really like this program. So, inkydigit, try it and post your comment so the others finally decide to try it too
On a final note, changing the color temperature of your screen is not a good idea when using Terragen, because of course, the colors change :p
There's an option to disable the program for an hour (or you can even quit it, of course).
