i actually don't like the way HIchigo / White Zangetsu's scream sounds... It feels like they threw it through the nearest distortion machine. On the other hand, his voice sounds freaking awesome when he's talking though. Hiyori's warped voice isn't too bad.

one small detail: This episode HIchigo started taking over slowly, and you could see the blackness cover Ichigo's eyes, representing the Hollow taking over dominion over his soul. I just noticed that the Hollow always starts creeping from Ichigo's left side, and that side is also where his mask first materializes.

It got me to thinking, is this just some random thing the mangaka decided to do, or is there something beside it? The only thing I can think of is that the heart is on the left side, so the Hollow spreading from there could be just a correlation with him losing control over his soul (assumedly located in his heart).

DB Hunter: White Zangetsu / HIchigo is calm when he's facing Ichigo because he recognizes that he is growing stronger while Ichigo is having more and more trouble containing him. He acts like a lunatic when he gets control over Ichigo's body because he finally gets that control, after being suppressed almost all the time.
I don't see him as a rabid dog, more like an incredibly happy kid on a syringe of adrenaline at a carnival; he's filled with delight at being let out. He always sounds like he's having a grand old time whenever he gains control. (He also craves destruction, like most Hollows seem to).