I used the trial some time ago but since I got new sound isolating headphones, I purchased it. It really does improve the sound (My tv has a similar technology to simulate surround sound, powered by WOW).
I think 30.00 or 40.00 bucks is a bit much though, if it was 20.00 then I would be much happier with it. I also like its auto genre detection.
The place it shines the most is for people who listen to a lot of electronic music (trance, house, etc) and people who have a lot of lower quality songs in their library.
I recommend it!