So, borrowed a friend's copy of Chaos Rising and have to say it was a pretty decent expansion. At only 8 hours long (give or take) it is rather short for 30 bucks, but it had a decent story and some nice improvements upon the original - notably the introduction of multiple objectives within a mission. The addition of the Corruption mechanic means I will get around to playing it twice, to see what the differences are if you go to the dark side, as it were. (I recall it being said the ending is different)
Not sure I liked the way the final boss looked - a little too cartoony if you ask me - but the fights were good for the most part. I did lament the fact that cover seems to play less important a role in this game and often fealt my characters were being left standing out in the open to be shot where in the last game they provided a great deal of terrain to provide a better illusion of point-to-point combat.