I think a lot of how people feel about Disneyland or Disneyworld is based on where they "grew up" so to speak. I spent my childhood going to Disneyland and did not visit Disneyworld till I was an adult and therefore Disneyland will always hold the "special" part in my heart.
Disneyworld is larger then life...the castle is truely a Castle. But Disneyland Castle is so sweet and fills me with joy every time I see it.
Disneyworld MK is HUGE...4 times the size of Disneyland but it has far fewer rides then Disneyland. I love both but the MK has more of a giant mall feel then Disneyland...while Disneyland at times can get overcrowded and the intimate feel isn't all that fun :lol.
Fanatasyland...someone mentioned the DL fantasyland was better but they couldn't put there finger on it. I can

Disneyland Fantasyland is actually little buildings each themed in the extreme! You feel like you are in a little Bavarian Fantasyland. The first time I walked into WDW MK I looked at my DH and said "Everything is a tent?"....now it is great but the "feeling" does not compare to Disneyland's Fantasyland...but there are so many other great things in WDW so it all evens out.
A small comparison of just the MK/DL Fantasyland
WDW Fantasyland has the following:
Snow White
Pooh (better then DL..but DL is by Splash not in FL)
Dumbo
Mickey's Philharmonic
Peter Pan (my DH thinks WDW is better then DL)
IASW
Carrousel
Tea Cups
DL Fantasyland has:
Peter Pan
Mr. Toad
Carrousel
Dumbo
Pinocchio
Snow White
Casey Jr. Train
Storybook Land Canal Ride (which is so wonderful)
Tea Cups
Alice in Woderland
Matterhorn
IASW (which on the outside is far superior to WDW)
I didn't put the race tracks in here since they are both sort of part of Tomorrowland.
Some have mentioned WDW has more of a vacation feel to it and I guess that depends on where you are coming from because either can feel like a Vacation if you are, Well on Vacation! We have done some of the offsite hotels in Disneyland and we have done the Disney Hotels...I feel the onsite Hotels are better and do give more a feel of "all Disney all the time" When we stay onsite we never leave even to go offsite to eat.
If you do Disneyland I would recommend doing the Grand Californian (although we love the Paradise Pier Hotel..the DLH not so much but that is just personal taste)...Do the package deal and you will have all the early entry privaledges (you do not have to have only
AAA...I am pretty sure Hotel guests get some EE...I know they do get in earlier to Toon Town as we have done this and many of our friends have).
Anyway DL is great. WDW is great. We love both but WDW is a rare treat for us since it cost much more then DL and is all the way across the country.