I just replaced a Power Director with a BPT 3.5 Ultra and am very impressed. I have not used the Hydra. So, I cannot help you there. However, if you go to Audiocircle.com, you will find a comment from a guy who had the Hydra 8 for a month and sent it back after he heard the BPT for 2 days.
Hydra 8/Hydra 6 vs PS Ultimate outlet?
Currently using PS Audio hc Ultimate outlet on preamp/cdp with VD nite replacing stock input AC. Any experience/comparison to the Hydra 8 or Hydra 6 and any rec's on input power cords incl non-Shunyata? I only anticipate using on preamp/cdp. Thanks.