After playing Starcraft 2 for a while here a small resume:

-Great Story and Mission in Singleplay.
They are really fun, and offer lots of additional (also
the old) units, compared to the multiplayer.

The Starship/Homebase enviroment between the missions is a grat idea,
and gives it some RPG feeling.

-Multiplayer is great as expected. Also taking some more thought
into getting casual players be able to play it
(wich was not the case for Starcraft 1)

-Bad bad Menusystem.
Somehow they missed to implement a coherent Menusystem into
the game. Its an unstructured mashup. I never know where Im currently in the main menus.
Blizzard did that much better in all other games.
Also the linkup into the Battlenet service is confusing.

Ingame the menu is ok, but not great.