My first impression upon seeing these new castle sets was not very good. However, after looking at them more, they do have their qualities. I still think they are pretty weak as a product line, but for parts they could be good if they aren't too expensive. Anyway, here are my thoughts:
8777 - knight, soldier, and catapult
Estimated price: $4 - $7
What I like: The catapult doesn't use that really bad one-piece catapult arm from Knight's Kingdom. Two minifigs, both of which have armor. New color for the classic sword. The horse has barding. The barding doesn't look gay!
What I dislike: The blue helmet. Maybe the black one too.
Comments: If it is $4, this will be an awesome army builder and I will probably buy several. If it is $7, I will probably buy a couple on sale, but no more than that.
8778 - rope bridge
Estimated price: $10-$20
What I like: Two minifigs. Some foliage and terrain building parts. Actual bricks under the staircase! The rope bridge has many interesting possibilities. The black helmet is nice. The harry potter keys always seemed cool, so I'm glad to see it in a castle set. Green plates.
What I dislike: I don't know if I care for that big blue sword. It seems too big.
Comments: If this is $9.99 or $12.99, I'd like to get a couple. If this is $19.99, it's not worth it Also, is there some kind of flipper to shoot that rock? I don't think I would like that, but I do appreciate the bricks, slopes, and plates present in this set.
8779 - joust
Estimated price: $20
What I like: Uh... well, I like the dark red color. The flags hanging by the king intrigue me. I want to get a better look at them. The wheels are good parts that can be used in many ways.
What I dislike: The king's podium is junk. Not much of an audience. Why can't this be more like 6060? Why do we need 4 more trans orange flames?
Comments: It appears as if there are launchers that fire these wheeled horses at each other. Not very realistic, but kids will probably have fun with that for about 20 minutes.
8780 - obstacle course
Estimated price: $30-$50
What I like: The green knight. Serpent head - made of fairly normal parts! Lots of equipment, including a trans-yellow spear and a new color for the classic sword. Several technic beams. Brown staircase part. Stained-glass window. Bars in windows. The wizard guy.
What I dislike: The set design
Comments: It appears to be an obstacle course. Push the rocks to raise the bridge, fight the guy with the axe, defeat the serpent, etc. I think the goal is to find or rescue the guy on top. The set design sucks, but it has lots of parts and I think it would be fun to build with. However, if it is more than $40, I won't buy it until it is on sale.
8781 - big castle
Estimated price: $50-$90
What I like: The brickwork around the portcullis is wonderful. The blue curved slopes are a nice added touch too. The diamond shapes on the front are great. The crossbow turrets are nice. Non-chrome versions of the large chrome swords in a variety of colors. The black knight's shield. Seven minifigs! Lots of 75 degree slopes.
What I dislike: The open design. The black wheeled thing. The stupid looking lion flags - but better than the lions on old knight's kingdom. Many 1x2x5 bricks.
Comments: Just another crappy raised baseplate castle, but this is probably the best of the crappy raised baseplate castles. The brick and slope designs around the front gate are very nice, and it has a good assortment of figures. Unfortunately, most crappy raised baseplate castles are expensive, and this one probably will be too.
Anyway, those are my initial impressions based on some fuzzy scans. After seeing these sets from multiple angles and in higher quality pictures, my opinion of them may change. So far, if the prices are right, these will be great for elements to use in our own castle creations.
8777, 8778, and 8780 are my favorites.