Before anything else, it must be said that both for a band as infamous as Meshuggah and for an album as anticipated as this, it must be some kind of record (yuk-yuk) for it to have NOT leaked up until 3 days before the scheduled release. Thats just fucking insanity.
In lieu of said leak however, I have only heard one of the officially tubed tracks, and this guys review here sums it up more efficiently than I can.
http://www.metalsucks.net/2012/03/15/review-meshuggahs-koloss-is-a-giant/
His opinion of the album is exactly what I was expecting after listening to Break Those Bones, but the great thing about Meshuggah is, you can always expect better than excellent.
For those of you into a steely song or two, but havent had your 'Shuggah cherry popped, go and pick up Koloss!