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?
i had two rgpcs,didnt like,have 1 quantum octave,1symphony and 1 symphony pro,my system did not improve with a ultimate outlet mixed in.
Highly recommend the Blue Circle BC86 Noise Hound. Two are better than one ($110 each).

Those little Audio Prism Quiet Line are OK at $25 each. Minimum of 4, and 8 are better put around the house near noisy refrigerators, etc.

I believe the Richard Gray 400 conditioner is parallel.

The Vansevers 85 and Reference 85 conditioner also uses parallel filtering, so not to limit current.

I believe the Seakay Line Rover is a parallel line conditioner. I've used one for years and find it makes a slight, but positive, difference. I am convinced it protected the electrical systems in my house a few years back when there was a lightning strike right across the street from my house; every house in a one block radius was affected except ours. Now I don't care if it works at cleaning up the AC or not.
Can't speak for all of the different models out there, but some can measurably and demonstrably lower the noise coming into the system. Sean
The MIT Z-Stabilizer is also a parallel conditioner - PS Audio has even commented on the positive benefits of using the Z-Stabilizer in conjunction with the Power Plants.