Had a read of the codex at my local
GW (got almost all the way through it)
every splinter weapon is 4+ poisoned, but has no strength, so no rerolls.
Incubi are well....really really really good for their cost.
Blaster spam has been somewhat corralled but is still possible.
Rumors of a melta lance, are true, but its statistically a little worse than a normal melta gun, and only available to a few units.
Pain markers are very very scary, and avoiding loosing units completely will be paramount to not being swept up in a tide of buffed eldar. (this is army wide not just wyches, and many uints start the game with them, mkae feall no pain
DE from turn 1)
The special characters were a little lackluster IMO and way too expensive generally (but there might be a few gems in there, didn't really look over them a great deal)
They are even faster than before (im pretty certain most if not all of their tanks have the ability to or an option to move up to 36 inches a turn).
They are really quite expensive vs their durability (more so than before), however they have gained a few things to make them a little more durable.
wyches are troops!
harlequins are in there (same as eldar).
Many units dont have grenades still (but most characters have access to a rather expensive piece of wargear, that gives them and the squad offensive and defensive grenades)
Haywire grenades are still crazy good, and there is a ranged haywire weapon (2+ to cause a glancing hit, 6s pen 24inch range) but I forgot to check what exactly could carry it.
some characters have access to blaster pistols!
Hellions can hit and run and abduct independent characters as they run (making a combat on their own away from the original), which coule be very bad for mekboys, sanguinary priest. and other squad buffing characters.
ravages can move 12 inches and fire everything! as can a few other vehicles.
Model wise, mandrakes are the best thing I have ever seen!!!!! my goodness me they are like dryads+fire+protos (starcraft)+awesome+samurai
(everything I can remember right now).
Games vs
DE will essentially be very very bloody whoever wins, they are the ultimate glass cannons. (and they are making me drop my current list which has two land raiders)