Both Warriors & Immortals have been downgraded somewhat, with Warriors having their armour save reduced and Immortals a large section of their stat-line dropped so they are effectively identical to the old Warriors (albeit with better guns).
As well as detailing the two troops options, I'll also be detailing the remaining dedicated transport options available to the Necron army in this post.
Warriors still maintain their 4 4 4 4 1 2 1 10 stat-line, however their saves are now only 4+ which together with the difference between We'll be Back and Reanimation Protocols has actually doubled the chances a warrior will die from a low-ap wounding hit. On top of that, obviously Ap4 weapons are now a huge danger, which certainly makes the warrior seem far weaker, despite the fact they now have better protection from Str8+ & power weapons.
Fortunately they have also dropped 5pts, to be only 13pts each. Some feel this is still a little expensive but with the Sisters of Battle point increase I can't say I'm surprised, I'd have expected 12pts but I'd also place Sisters at 11pts so what can I say?
Either way they are somewhat cheap, especially since they can now be taken in 5man units so many lists will still use them I expect. Interestingly not only do they have access to dedicated transports now like most Necron units, but one of the transports (The Ghost Ark) can only be selected by Warriors, making it strange that GW released this model first and not the more regularly select-able Night Scythe.
Whilst downgraded from their previous stats (which the new elite units inherited) they still have full marine equivalent stats (Ini/Ld aside), which together with Reanimation Protocols makes them slightly more survivable than marines (outside of combat, I'd say marines And They Shall Know No Fear still makes them far better there).
Their basic weapon also had its stats downgraded, yet they still have one of the best standard weapons available to troops choices. Gauss Blasters have both one higher point of strength and one lower Ap than bolters, as well as having the Gauss rule enabling them to glance any vehicle.
Immortal units are also able to exchange these for Tesla weapons (24" Str5 Assault 1) for no points difference, enabling the option between better Ap & more shots at close range or a chance at additional shots at any range. I'd still take the Gauss personally, not only due to the Ap but because of the Gauss rule itself.
~ Dedicated Transports ~
The most expensive transport at 115pts, although not much more than the Night Scythe and of course the Ghost Ark is only available as a dedicated transport choice for Necron Warriors (although it can also transport Overlords, Lords, Crypteks & the special characters).
Like all Necron vehicles it has all round 11 armour, but it has Living Metal and Quantum Shielding which gives it considerable starting protection for a troops dedicated transport, although it is Open-Topped. It is also a skimmer (like all Necron vehicles) and can hold up to ten models limited to the types noted above.
Armament-wise it has two sets of five Gauss Flayers (the standard bolter-like statted weapons used by Warriors) which are able to target a different unit each. This alone makes the transport quite unique and maintains a moderate array of fire as it moves 6" about, although line of sight may become an issue looking at the model.
The Ghost Ark's iconic ability and what makes it such a dedicated transport is its ability to repair Necron Warriors. At the start of each Necron turn it can add D3 Warriors to a unit within 6", although as its repairing this can't take the unit above its starting number. Unfortunately there is a 1-in-6 chance the Ark will take a glancing hit each time it does this.
The main Necron transport, available to quite a number of units. It unfortunately lacks Quantum Shielding (yet does have Living Metal) making it one of the weaker vehicles but makes up for this by having the Deep Strike, Aerial Assault & Supersonic rules (the latter two enabling it to fire all its weapons at cruising speed and go 36" flat out), although since it only has one weapon its a mystery as to why it needs Aerial Assault.
The weapon itself is the powerful Tesla Destructor which is twin-linked as it always is, enabling it to potentially damage a multitude of units if clumped together.
The transport capacity of the Night Scythe is entirely unique. It can transport up for 15 models and unlike other vehicles it can carry Jump Infantry and Jetbikes (taking 2 & 3 spaces respectively), although since such units in the codex can't take a Night Scythe I don't see this occurring except in really long games.
The most unique feature of the transport capacity is that the models in transit aren't inside the Night Scythe but on the far side of a wormhole it creates. Whilst this allows the vehicle to count its entire base as an access point, it has the rather odd downside of if/when the Night Scythe is destroyed the 'embarked' unit cannot disembark from the wreckage but are placed in reserve (where they can't deep strike from, even if normally able to).
This is a big downside in a great many cases although it does mean you can, towards the end of the game, embark a unit and your characters in order to prevent their destruction in Kill Point missions.