Mad Dog,
The ElectroClear is cheaper (10+ EC = 1 Sym Pro), and even already with the Symphony Pro in the power route, you can still hear the improvement.
If you do a search in forums, you could see recommendations of using filters/conditioners after a balanced isolation transformer. Parallel filters/noise absorbers' effects are usually acculmulative, unlike serial filters, thus, you may find benefitial to have a parallel filter even you already a Hydra.