My local GW store has an advanced copy of the new IG codex. I spent the better part of a 1/2 looking at it yesterday. Here is what I picked out of it, the ref sheet that was leaked was correct for everything I compared it to. The Squadron idea is true for almost every vehicle (ie hellhounds, tanks and artillery) and it is any combination of those vehicles so you can have a Medusa and a Basilisk in the same unit. The average guard squad is 50 pts for the 10 guardsmen, in addition veterans and penal troops are the other troop choices. Comd squads dropped a fair amount in points Russ tanks start at 150 and go up, way up for plasma sponsons. All of the special characters listed in the rumours are there but a bunch of them are upgrade character for your Platoon Commanders or Veteran Squad Commanders. The new Elite choices are going to be fighting for a spot in the army, storm troopers, ratlings, orgyns, enginseers (who now repairs on a 5+ and can have 5 servitors) and the primaris psyker squad with two crazy powers (large blast at Str = # of psykers or unit within 24" is Ld - # of psykers in unit for the rest of the turn to minimum of 2). The adviser units are cool and I think we will see them here and there but the Master of Ordance always scatters even if you roll the hit it scatters in the direction of the arrow on top, but if he can see where he is shooting then you can subtract his BS. Hydras are 75 pts and come with 2 twin linked long barrel Autocannons, they can also be taken in Sqns. Orders are as they were rumoured, the Coy Comd can issue 2 and Pl Comd can issue 1. Creed can issue 4 of them and another awesome one that makes the unit fearless and give furious charge. Valkyries are 100 pts and are just listed as fast skimmers so they will only move 24" flat out which is a good thing IMO.
All in all I would say that it is going to make the guard one of the better armies but it is another case of way to many shiny new toys in one book so you won't see them all in one list. The biggest thing for me was, I need to start painting more guardsmen!!