There's not much more to say - I think Electrohound summed it up pretty much perfectly. I've been a follower of Underworld since the Lemon Interrupt days, and I would agree that this is their best work. This opinion is of little use to fans of course, who will have Oblivion With Bells already, but if you're not, and perhaps you still associate Underworld solely with Born Slippy, then I urge you to give this record a try (on a really lovely Denon if at all possible).
It's a full, rich sound throughout, weaving layers into the dark minimalist style of The RiverRun Project. If A Hundred Days Off was a slightly disjointed, transitional record, then Underworld seem to have found their truest, most coherent, most melodic sound to date. It's no coincidence, I'm sure, that this latest record opens with its most bombastic moment - the tech-funk of single Crocodile - before gradually descending to a kind of multi-layered ethereal canvas - here is a band saying "goodbye" to crowd-pleasing big beats (although they will say "hello" again whenever they play live, I'm sure).
With Always Outnumbered, Never Outgunned, it could be argued that The Prodigy, similarly, found their true voice - only for it to be their downfall. No such fate for Underworld, I'm sure. They are true electronic innovators; and here is their most innovative, most rewarding work yet.
Oblivion never sounded so good. I, for one, can't wait to hear what lies beyond.