It's awesome that a band mixes fast and slow; sometimes it works, sometimes it doesn't.
It's cool that you guys want to have a discussion..
What specifically do you like about GFM, aside from the fact that it's cool that the band tried a different style?
I didn't like GFM because it was "different" from their other releases. In fact, I'm normally not a fan of bands changing up their style just for the sake of it. Even if you didn't like it, it's hard to understand how you can't see its merit as a solid rock record. The first half of the album isn't that much different from U&D, just a bit slicker and slowed down. It's solid pop punk. Best I Ever Had is one of the catchiest, most provoking, pop punk songs of the past five years (imo). Some of those songs, especially 'Warming Up,' grip me on every possible level.
Maybe you got the laid back/lazy feeling because Nick sang lower on it? I know the band put everything they had into GFM, probably more than any of their previous releases.