Hai! I saw your sig.
Sky is definetely worth it. I got it in October, a week after it was released, so I'm pretty high leveled now.
Spinda's Cafe and Kirlia's dungeon are really nice add-ons, recycling and binge drinking can raise your stats, give you rare items and unlock new dungeons and pokemon recruits.
The Mime Jr's spa is great too, restores your belly, PP, HP, etc for all your team for only $100.
The new partner/player pokemon are great, and you get an egg move too.
And the Special Episodes are a fun side-adventure.