...Well, it's epically pretty - but what did you expect? It's a Forgeworld book.
The army list is kind of cool, though. Essentially an entire Necron Dynasty that's succumb...ing?...ed? (take your pick, really) to the Flayer Virus. Resulting in a vast army of mechanical nutters.
The two special characters are interesting. Klutakh is the really, really harsh one - a Necron Phaeron capable of going toe-to-toe with just about anyone and kicking their teeth in in a fair(ish) fight, without needing to resort to dirty tricks like mindshackle scarabs.
Most of the list is unchanged (give or take) - warriors are warriors and immortals are immortals (although you get limits on the latter). Lychguard are also steadily going nuts, so are slightly more expensive but marginally tastier in a fight.
The key differences (or additions, I guess, since they're available in the normal book) are the tomb stalker/sentinal, the tesseract arc and the bomber - all of which are cool but not game-changing, as there are existing analogues - but more importantly the addition of flayed one troops (which are extra stabby thanks to their extra upgrade option) and anti-personnel scarabs makes for a more assault-focused list.
The second big change is the addition of the fortification - essentially an entire board tile with an invulnerable save and improved reanimation roll for anyone stood atop it. Park some Gauss Exterminators on the emplacements (essentially giving you 4 icarus lascannon mounts) and laugh like a drain. Docking a monolith is an expensive option, but increased strength monolith weapons gives you impressive protection against anyone trying to storm the fortress...