On the evening of this codex's release, my wife flips through the book to feign interest, and announces in summary: "I don't like this book. There's too much boobs."
She was kidding.
Other than the general fact that it seems Druchii women don't wear much in the way of clothing throughout the book, and taking into account my general lack of knowledge of what makes a good army in Fantasy through lack of experience, the book seems pretty strong. For one, the entire army gained the abilities Always Strikes First and Murderous Prowess (which has been giving people spelling fits for weeks when rumors leaked and gives re-rolls of 1s to wound in combat).
If anything, magic got more powerful, with casters coming down in price across the board, getting +1 to cast Dark Magic, and Dark Magic having what I think are strong Signature Spells and a cool (if probably mostly ineffective) Attribute. Doombolt is one of two signature spells to choose from and is cast on a 12+ (or overpowered on a 24+), and deals 2D6 S5 Magic Missiles (4D6 for the boosted). The Black Horror seems very strong but very risky, with it landing on the caster's head on a misfire.
The magic items seem pared down and generally nothing stood out to me as being particularly good.
As for the units themselves, the characters generally dropped in points (Malekith, Morathi, Hellebron, Sorceresses, Shadowblade, Lokhir, Master, and Death Hag. Assassins were moved (back) to heroes, and Malus was bumped up to a Lord, having that bump and price jump of 20 points offset by increased WS, BS, W, I, A, and getting a Sea Dragon Cloak. Similarly, Tullaris and Kouran got bumped to heroes, and got some across the board boosts to their stats, including a second wound. There are also two new Lord entries, a Beastmaster, who comes with either a Manticore or Scourgerunner Chariot (new unit), and a Black Ark Fleetmaster.
As for mounts, they generally became cheaper, including Manticores (now 25% off) and Black Dragons. However, the Cauldron of Blood became significantly more expensive.
In the Core section, most units became slightly more expensive. Corsairs went down a point but lost their second weapon, which can be purchased for 2 points, making them 1 point more expensive. Interestingly, Harpies moved to Special, which is now extremely crowded, and jumped in points, ensuring they probably won't see the table. On the other hand, Witch Elves moved to Core and were bumped a point.
Moving on to Special Units, Black Guard went up a couple points while Shades and Executioners remained mostly the same. Cold One Knights bumped up 3 points, with their mounts gaining an attack. Interestingly, Reapers and Hydras both moved to special and dropped in points. The Hydra gains an attack (essentially), but loses an attack with each wound suffered. That said, at the end of each controlling player's turn, they regen each wound on a 4+. With the drop in points and move to Special, there's no reason the Hydra won't stay popular.
Finally, the rare section, which is where nearly all the new stuff resides (with the exception of the Scourgerunner, which is a Dark Steed chariot with a special bolt thrower and is Special). The Medusa can be fielded alone or on a Shrine, is faster on foot, but obviously benefits from being on the Shrine in terms of survivability. She is pretty brutal in combat (with her abilities), but has a shooting attack as well. The Kharibdyss is the same price as the reduced Hydra, but is a bit stronger in combat with higher weapon skill and strength, and will not lose attacks with wounds. It's special attack is interesting, but will probably rarely come into play; it deals extra damage if it hits with all of its attacks on a single model.
Finally, there are the Doomfire Warlocks (which will be in a dual kit with the new Dark Riders) who, as a unit, are a Level 2 Sorcerer and can pack a decent punch in combat for Fast Cavalry, and the Sisters of Slaughter, who strike me as slightly different Witches.
Of the unreleased units included in the book, you get a couple limited glimpses of the Executioners/Black Guard and the Doomfire Warlocks/Dark Riders. I have to say I like the Executioner/Black Guard kit, they seem nice looking, although the black guard look rather static, with one hand just hanging at their side. The Dark Steed kits I'm less of a fan of. From the pictures, to me anyway, the horses just don't look right.