Just got off the phone with my GW Rep... Here's some info:
Collector's Edition will be a very high end version of the actual rulebook. He hasn't actually seen it yet but think leather bound, fancy gold edging on the paper, higher quality paper, etc.
Gamer's Edition will be identical to the normal rulebook plus dice and a satchel.
Gameplay stuff:
Models that are killed MUST be removed from closest to furthest.
No more wound allocation.
Cover saves are either 5+ or 6+
Players may premeasure.
Random charge length.
Players will be able to "buy" fortifications. Want a Defense Line? Cool. Want a Fortress of Redemption? Cool.
There IS an allies chart.
No percentage based Force Org
Feel No Pain is 5+
I was told, "It's not a completely new game like what happened from 2nd to 3rd ed, but players WILL have to relearn the game on the 30th."