Gave it a full listen via the iPod/Senheisers (320K AAC...so its not too badly mangled), then a partial listen on the main rig.
As for the songs....killer stuff.
Funny thing. Its still guitar/bass/drums/voice, but there is something unique about the sound and the tunes that does not leave me thinking that its just so much derivative crap, like a lot of other new music. It all sounds original to me. I guess Perry just has a very distinctive voice and vocal style.
Sonics....well, its a mixed bag. The overall blend is a bit rolled off on the top. The bass and drums do have great impact, and the guitars are prominent in the mix, but as usual, the cymbals can sound a tad harsh and congested on certain tunes. Not the worst offender, that's for sure, but it could be better.
But overall, I like it a lot. And yes, there are some really cool guitar solos, but always in service to the song. No gratuitous wankery at all.
BGL