I've put around 150 hours on SC.
SC2 has been out in arcades for almost a year, but I haven't tried to play it yet.
From what I hear, the main change in the engine is in the 8WR, which is tweaked to make the game play faster than original SC.
But the thing that sells me on SC2 is Weapon Master Mode.
I'm itchin' to kick the shit out of my friends with a tambourine wielding Voldo.
EDITS: P.S.: SUPER COOL IMPORT INFO ON SC2.
http://www.felixmcli.org/sc2-main.html