I have to say that I love most of the sets.
Riddles - Nice brick built rock and 2 great figs. I like gollum's new expression. The parts are useful.
Mirkwood Spiders - The new leaves, webs, and mushrooms are sweet. The elves are awesome as are the weapons included in this set. the build is meh...
Warg attack - I like the warg mold. The colors are just ok. I hope we get some tan and brown wargs in the future. That tree is just ugly and horribly designed. I do love the olive tree parts though. The orc leader is a pretty ugly fig.
Unexpected gathering - This is a breat build. The green and neutral color parts should be pretty useful. I like the little extras like maps, food, in the set.
Barrel escape - This is an attractive build of nice neutral colored bricks. The elves again are incredible. I love the big barrels, bottles, goblets, etc. very useful.
Goblin King - I think the terrain looks great in this set. These parts are very useful. The goblins look pretty good but the skull caps make them look a little top heavy. The goblin king turned out much better than I thought he would.
The biggest thing for me in these sets are the torsos. Only Kili's has a small splash of flesh as far as we can see. If TLG were to release civilian castle sets yearly for the next ten years I doubt we would get a variety of colors and style of torsos the dwarves give us! Just look at the nobles, adventurers, peasants, and merchants you can make with those. My castle world is going to be much more diverse with these available. I will be adding these to the LOTR torsos in my collection.
Deskp on Eurobricks made this photo for comparison.
You can check out the larger image of all of the dwarves here http://i45.tinypic.com/1191ppu.png