"[Barber Tone Press] allows me to change the mix balance between a compressed signal and the uncompressed signal, thereby allowing transients to break through, while the sustain continues underneath," says Henry Kaiser, in [this article](http://www.premierguitar.com/articles/Henry_Kaisers_5_Essential_Effects).more
Back when this pedal first came out, it was one of very few compressors I was aware of with a blend knob to mix in some or a good bit of the dry signal. Since then more compressors include this feature, and they sound quite good, but I've stuck with my trusty Tone Press. It has a sound. I like it quite a lot. Also works well as a front end boost if need be.