I've had my Helios for about 2 weeks now and am still amazed by it. The constant volume DSP feature is very nice and is extremely handy when watching movies/TV while my kid is asleep. It normalizes dialogue and effects so there are no unexpected loud sounds that could wake him.
From an audio performance perspective the soundstage it creates is extremely dense and full of detail, but not an in your face presentation. It's very organic and smooth, and the bass performance is off the charts good.