I've just purchased second hand(£175) a speedbox SE 1 to go with my pro ject perspective 1. I've just been listening to it, then swaping back to no speed box, the more i listen to it the more i like the sound, smoother, more assured, seems to be less background noise, a more solid grounded, deeper sound, bit hard to describe really. Its not been a massive change, more subtle buts its deffinately been enough that if i were to take it back I would always be listening to my deck thinking I was missing something....