I *mostly* use AHP *exactly* the same way Forrest Snyder does: That is, I use it to boost the audio quality of iTunes and Spotify in particular.

That being said I have successfully used it to mix audio effects channels when running live interactive games using Skype and Quicktime etc.

It really is a VERY fine bit of audio kit that I recommend to EVERYONE.

However, I can't see any great advantage -- for me -- in this new app. I HATE with a passion the flat, bland colour scheme used in Yosemite and happily await the day when colour is no longer considered an insult. I say this as a visually impaired user and as someone who works in disability where colour and shape offer the user tremendous advantages. But this is not the place to rant about Apple's design choices. :-)

As mentioned above I use AHP to enhance audio, and I use the VU meter -- which you can place anywhere on your desktop(s) -- and the In RMS to gauge what's going on. The new VU meter is pretty horrible and, I note, stuck in the UI.

I've also got to say I'm not keen on the multiple windows. AHP was a one window shop and that worked quite well for me.

You guys will probably get an upgrade payment from me, just so I can stay in the loop for AH4, but I will be using good old Audio Hijack Pro for as long as I can run it on my Apple OSes.