(Apocalypse, in macro form)
They also toned down the horribly broken combos, and while there are a few solid choices to be made there aren't any no-brainers. StrD is not so bad as some make it out to be IMO. Highly effective at killing vehicles as always, but there's a 1 in 6 chance it will do nothing to infantry.
One thing I don't like is the new "after the break" system for some things as it's a bit too meta for my tastes (and I usually love meta stuff). I understand it as a concept and I do like that they've included more of a guide for organising, but tying rules to when you have lunch is a bit... odd.
Not a huge fan of keeping most vehicles off the board either by restricting their entry, but I see why they did it. Still no big deal and I'd rate this version 50% better than the old one.
As for my thoughts on specific dealies...
Flank March - now only brings on one formation. Did you know you can have 200 Necron warriors in a formation?
Trophy Kill can be good as it's easy to vapourise people with StrD now and earn an easy 3 VPs to recycle Titans over and over with.
Tunnel Rats could be used to hilarious effect with Precise Coordinates to deploy gigantic swathes of IG to the board up close and personal.
Most of the Space Marine ones are kinda terrible, mostly due to small scale or not particularly epic effect.
Daemon Shell got improved as you don't have to nominate who has it until you shoot it.
Ere We Go can't hurt in the world of random charges.
Idol of Gork (or possibly Mork) - give you Rage! Must be in your deployment zone... uh, no.
Mek Workshop - restores vehicles to full hull points. Combine with Stompa Mobz and have everyone hate you.
Strands of Fate. Good for bragging rights or just being an insufferably smug Eldar player. Unless you roll a one in which case play it off as a joke.
Webway Assault - crazy good, especially when combined with the Kabalite Web Strike to give you four vehicle accessible portals anywhere on the board.
World Digestion - still as annoying as ever.
Entropic Plague - everyone will hate you. Forever. But you're playing Necrons so that should only make you more powerful.
The big change is that Formations are now free - so if you have the models just whack them into one because there's only benefits (aside from needing to squadron up).
Some interesting things about the changes to Superheavy vehicles are that, aside from being unstoppable killing machines, they're generally faster, can be targeted by psychic powers (Baneblade with 4+ invulnerable!) but can also be locked in HtH combat, which is a huge change with how assaulting Titans will play out. Before with having to disengage each turn it left attackers vulnerable to countercharges and being shot to death. Now they can tie up a Titan much longer. I think StrD melee weapons will be a little more common now out of it, as most Titans don't have a high attack score to just bludgeon their way out of combat (even with Stomp attacks).
High Commands are also basically amazing as they give you one free Strategic Asset during the game.
Anyways, arm up, and let's look at what's cookin':
Lord Castellan's Command is a great choice for an IG army, with lots of benefits at a relatively low points cost. Trick is to keep Creed alive of course.
The Space Marine Companies are both good, especially if you're planning on taking them anyway. The only downside is you have to deploy them all together. 1st Company is a bit better as it gives everyone Deep Strike and Fear as well as lots of other benefits.
Wings of Sanguinius can deep Strike in the enemy's turn, meaning next turn (if they survive) they can run around and assault and so on.
The GK Extermination Force is probably the only formation I would come close to calling broken. While it fits the background if you bring it against Daemons in particular don't expect many invites again. It does have the weakness that the Dreadknight is the key so it's not that dangerous.
The Lord of Skulls is perhaps a little overpriced (I must meditate on this some more), but not hugely.
The Tetragon of Darkness isn't anywhere near as annoying with the change to StrD weapons.
Dread Mobs are a great investment for any Waaaaagh.
The Stompa went up in points..? I'm not seeing why.
Phantom Titans are good now, really good (assuming you can keep them out of assault). The D-Cannon did lose the ability to ignore shields, which kinds blows, but the new Superheavy damage rules really benefit the Eldar the most.
Sunstorm Squadrons got even crazier and will utterly annihilate huge chunks of the battlefield easily. One of the deadliest formations in the book IMO.
Fielding a Wraithknight Dreamwalker Squad is nifty and could really catch people off guard when they start running around 11" a turn.
All the Dark Eldar formations are good, but Dark Olympiad (even better with the Duke)and Kabalite Web Strike are the stand outs. Everything in the book for the DE works so well together they can easily be a top Apoc army without any Superheavies.
Endless Swarm is kinda insane as after turn 4 you can only Snap Shot at it, and it is theoretically infinitely large...
The Heirophant has been fixed up so it now actually has workable rules, and I don't think is either borked or over priced depending how you look at it.
The Necrons are a real mixed bag. A few don't seem very good due to either just not being very good (Obelisk - very situational) or impractical (Baleful Necropolis - stay within 3"? Why, yes, I do want lots of StrD pie plates!). Infinite Phalanx is funny as it's a single 50+ warrior unit. The downside is that it's all one unit so can be bogged down in HtH by a few guys for a long time.
The Tesseract Vault and Transcendent C'Tan can be dead killy (the C'Tan especially), but can also be very, very pricey. You can easily make the C'Tan cost over 800pts, and it will wreck face without doubt, but it also explodes horribly when it dies so...
The Macro Cannon Aquila is a fairly cost effective way of getting StrD and an AV15 bunker into the deal. The Vortex version isn't as good simply due to the Vortex rule changes.
So that's my thoughts on the first pass of the book. Not necessarily accurate, not necessarily final, but certainly there. Or here. Or whatever.