well i wasn't sure of what to think the first time I heard it.
i loved the first four songs and then i thought it dropped off kind of and picked back up with "the hardest part."
originally i wasn't too crazy about tracks 5-9, but after having the cd on repeat... "X&Y" has emerged as one of my top three songs.
that song is totally different than anything Coldplay has ever done.
at the moment it sits somewhere between parachutes and ROBTTH.
it certainly is a good disc, but i do miss the piano.
however i said the very same thing when radiohead ditched the accoustic guitars for a more experimental electronic sound.