I have only done 2 character meals so far:
Chef Mickey: Very laid back, casual, buffet-style (more 'fun' foods for the kids to choose from for the pickier set, especially), very upbeat & interactive
Princess Breakfast: More 'formal' (not stuffy-formal), choice of 3 items (IIRC), but absolutely precious--totally different experience but equally enjoyable. There is interaction here as well with wands given to girls and swords to boys, and a litle wish making 'ceremony'.
Both have picture pack included in price.
Hoping to check out Crystal Palace next trip; it seems a such a basic thing to rave about, but absolutely love the way the characters are so attentive to kids and make them feel so special
I like the earliest breakfast a lot because then you have this magical experience of walking into/through MK before it's 'open'. I could not believe the pics we got in front of the castle and down Main Street.
Also, for us anyway, breakfast is a great meal to start a busy DW day; then we can 'walk it off'

I am just not a big luncher.