There are now 16 Darkstalkers characters. Donovan, Pyron, and Phobos are gone, and four new characters have taken their place:
Jedah (a Red Riding Hood lookalike)
Bullets(young girl, big guns, and a dog)
Q-Bee (half-human, half-bee, all woman)
Lilith, Morrigan's mother (or sister).
Some great backgrounds have been added, too, including one where it looks like you fight on the side of a building.
The game is based on the older CPS2 board, the same used to do Street Fighter Alpha 2.
Release date for Arcades is roughly same time SF3 officialy comes out.