The IA's have some big changes in them...
IA1 Has the Valk and Vulture rules updated... The Punisher cannons are unfortunately TL, I'd rather have 40 shots...
No Rules for said Punisher cannon I could see other than it being Twin linked.
Both get Flyer rules for Apoc games for Free.
Get this Thunderbolt... NO AA mount on the Auto cannons any more
Get this Lightning HAS AA mount on Auto cannons.
Hydra...AA mount and auto targeting system...
Manticore 3 missiles now including AA missile
Dread drop pod is an Assault Vehicle now... Your Dread can now Assault on the turn is comes in...
LRC 16 troop slots...
LRH 6 slots
LRP 10 and Battle Auspex rule... Night vision and -1 to all cover saves.
The new Ork stuff looks awesome too, only downer is that the new truck/tracks don't have weapons and you have to buy them separately or in a combo... Kinda like the Titans now.
The Grots are Funny as Hell too.