If you're looking at this becuase you liked Boys and Girls, then you should go ahead and get it. Excellent though Boys and Girls is, I slightly prefer this. The formula is pretty much the same, but Separation Sunday seems to give no ground at all to any thoughts of commercial viability (there's no whoas or funny keyboard figures in the choruses) and I think that improves things, by making the whole a bit purer and more coherent.
On top of that, Cattle and Creeping Things is one of the best things I've heard in ages - musically and lyrically it's spot on, and there's plenty of other great riffs and smarty-pants wordplay on here too.
So if you like your rawk music with a brain on it, do yourself a favour and get this.