Razer Surround Free

It was, but it'll get a price :P

It works as far as I've tested it, really helps on shooter games, mainly Arma to know where the shots are coming from. And horror games get a boost in reality if you have a common headset.

I'd say it works very well, it really helps creating a sense of space and helps with positioning. If you play games with a headset, some form of virtual surround is a must imho.

An easy way to check out Virtual Surround is to look on Youtube. There are several videos comparing the various solutions, like this one or this one. To get the full effect, make sure to turn off any audio enhancements or EQ you have on before viewing.

In my opinion, it doesn't work. I've had it 2 times and both time I had no audio. I googled it and found that it is really common issue. Tried some fixes but they didn't help.