I definitely see why fans feel divided about this new album. While rather different from the amazing Viva la Vida in its celebration of life and death, Mylo Xyloto definitely breathes an alternative almost playful side to the band's usual themes.
It's different from what we're used from Coldplay but you can still hear a familiarity to it. If I had to compare it to other bands, I'd say some tracks have a remarkable Sigur Ros feel to them, what with the metallic echo sounds and chorus in some select tracks. The duo with Rihana was done well, against (many) dreaded expectations.
Overall, a different approach to a great band in an album that (I feel) gathers a little piece from every corner of the world. Not their best work, but you shouldn't let these words discourage you if you're a true fan. Also, they've set their bar high with their last album, so it will be difficult to break those odds.