Played two games today. Quick thoughts:

Game One opponent was a Ravenwing Deathstar. Black Knights (couple units) huddled around Sammael and a Darkshroud with an Apothecary and a Banner for +1A. Tore through everything and while -1 to hit everything doesn't seem big, it actually is quite damaging. Was surprised at how powerful this setup is. He ran it alongside a Knight, but I honestly think he would have been better served with another unit or two of Black Knights around another Darkshroud to smash two sides of the table at the same time. Lost narrowly after some poor rolling and positioning, though killed all but 9 of his models. Tied on points, lost to FB and StW.

Game Two opponent was Dark Eldar, multiple units of Reaver Bikes and 5 Venoms. Holy crap he had a lot of shooting, and it was all extremely fast. Not an optimized list, though, I won handily after blobbing over all the objectives with my Infantry and blitzing up the board with Wraiths and the Nightbringer, holding him back until he finally cleared it on bottom of T3, but I'd already cleaned up a good portion of his army as well.

I tried a few things:

-Cryptek-backed Warrior blobs are great, they just eat shooting. Not as invincible as before, but people really focus on taking them down all the way to prevent RP. Smart, but I'll take an entire army's worth of shooting on my cheapest models and be ok with it too.
-C'tan Nightbringer is strong but still really should be careful. I threw him out solo in both games and regretted it. 4++ still isn't great, even with 8 Wounds. Worked better when paired with Wraiths (not as fast as them but still pretty fast) than just standing behind Warriors.
-Wraiths are still good. Haven't changed a lot actually - don't expect them to kill much but also don't expect them to go down without a fight. I think the AP-1 is better than Rending honestly, and hitting on 3+ naturally is a blessing. The new wound chart also is a boon, since you're never wounding on 6+ without some sort of shenanigan.
-Doomsday Ark, not sure on. Very strong, but we played on really terrain dense boards (as I think you're supposed to) and there was plenty of times I had to take a less than optimal shot so I didn't have to move. Comparable to 2-3 Heavy Destroyers, but honestly the mobility may just be way better.
-Monolith was... I dunno. I may have just used it wrong, but it did nothing. It's better than before, because I actually got to put it down on turn one and shoot things, and it survived multiple turns, but man, 4+ to hit is just garbage. How do Tau do it? Oh yeah, by having way more shots and ways to get boosts/rerolls. One game isn't indicative, but I'm really hesitant to put it down again.
-Deathmarks were also odd. S4 AP0 guns suck, but for 100 points getting DS and the chance to plink out some MWs? That's not terrible. It's not great, sure, but it isn't the worst thing in the world. Super cheap and the ability to pop up and threaten sides is interesting, but maybe not amazing.
-Crypteks handing out 5++ makes them autoincludes. Seriously, watching Warriors shrug off Plasma is a hoot.
-Heavy Destroyers are... expensive. Chunked down a Knight super easily, and blew up a Venom in a volley, but 75 for a single shot per turn is hefty. Again, this really depends on how heavily the meta goes towards spamming big things like Knights, WKs, or Nidzilla lists. I can see myself bringing 6 easily, but I can also see myself bringing none.

Next games will be on Wednesday probably, gonna try out Night Scythes I think. Dropping before movement and no longer forcing snapshots makes me a bit more iffy about taking them, but I can see really good things from plopping down 10 Immortals. There's also the hilarious idea of putting 20 Flayed Ones in a Night Scythe for even better surprise violence than their regular deployment. Flayed Ones in general will also make an appearance, I think, as will regular Destroyers or Tomb Blades.

The C'tan + Wraith "star" is pretty interesting - Wraiths now are amusingly one of our cheaper options (they only went down a bit, but everything else went up) and they can deliver Nightbringer/Deceiver to combat quite nicely. Fast, killy, though expensive. Still, I think it's better overall than Warscythe or even Shield Lychguard stars, which are super slow and can just get cut down before they get across the board.

Necrons still are wildly between low shots/high damage and moderate shots/moderate damage, with no real mass damage shooting unit, more focused on attrition. But we're good at it as well, and a lot of the changes benefit us quite a bit.