Basically this stage didn't get too mcuh discussion, I think we should discuss it again after we do the other ones.
I used information out of this thread too come up with the summary, credit goes to the original posters.
Castle Siege
1st Tier
Pros:
+ Platforms assist Mario in Fireballs.
+ Platforms aid the Aerial Game.
+Platforms are excellent for combos. Blast zones are perfect for Mario's K.O'ing, easily.
Neutrals:
+/- I've always noticed that the ledges here work kinda' funny... straight wall down the sides, kinda like Yoshi's Island. I guess this is a plus, since you can Wall Jump.
Cons:-?
2nd Tier
Pros:
+ More platforms are present, helping Fireball/Aerial game even more.
+If you are close enough to the blast zone your back throw is a free kill.
Neutrals:
+/- The statues cut off projectiles, both yours and your foe's.
+/- Very wide floor.
Cons:
-Walkoffs on this stage is hectic, and chain grabs can wreck you.
-Floor means Mario can't put his edgeguarding game to work.
-High cieling makes it hard to K.O vertically.
3rd Tier
Pros:
-?
Neutrals:
+/- Tilting floor can make or break both approaches and recovery.
Cons:
-High ceiling.
-Stage tilts a lot and can make or break your recovery.