I've heard the entire album and think it's great (It's currently being streamed on the official Paramore website if you want to take a listen). It's nowhere near as lively as Riot, but the songs are brilliant nontheless and it's unmistakably Paramore. The standout tracks for me are 'Careful', 'Turn It Off', 'Feeling Sorry' and 'All I Wanted' (where Hayley hits such a highnote that it gave me goosebumps, lol).
I think you've definitely got to give it a few listens before you fully appreciate how good it is though. I was a bit underwhelmed when i first listened to it (mainly because i was expecting something a bit faster paced like Riot), but it's grown on me a lot. I don't think there's a bad song on it tbh.