Anyone with parralel line conditioner experience?

I'm considering adding a parallel line conditioner. Marigo Labs used to make one called Transparency, I'm also looking at the Quantum Technology Symphony Pro. I have the following equipment: Levinson #380s preamp, #336 amp, #360s dac, #39 transport, Revel Salons, Cables by Synergistic. I'm also using a PS Audio P300 with Multiwave on the front end and have direct AC lines run to all components.
Does any one have a different choice or favorite?