Dragging this back up a bit, but I'm playing this through at the moment.
"Bring down the sky" took about a couple of hours to get through, I attempted it at about lvl35ish and pretty much walked most of it. the Story is OK, it's not up the main story line in the full game, but it's similar in feel to the bigger side quests. Some of the combat was challenging, which to be honest makes a refreshing change.
As to how good the game is, it's pretty good. It seems a little disjointed in places, pursuing the side quests really makes the main quest lose impetus. I'm getting a bit fed up with ident-i-kit stations to explore in the sides too. Last night I jumped back onto the main plot, and that is a lot better. I'm mostly enjoying the game but I might have to ignore a few sides, or I'll stop playing.