I use the rocktron Hush SuperC (rackmount), and i don't have problems with it sucking tone, unless i set it up incorrectly. It makes everything quiet when i'm not playing. Wee! I've heard the pedal Hush units when compared to the rackmount, they're not even close. They suck the tone right out unless you play somthing were a specific tone or frequency really doesn't matter. I prefer the rackmount hush, it doesn't suck tone if it's set up correctly. it may be because i run the rackmount hush in the effects loop of my amp, but i doubt it.
Also, as an after thought, using good cable won't fix line noise, and if you're concerned with your tone, i wouldn't use George L cables. they can't touch a monster cable.