If you are going to WDW February 1 or later, without question EPCOT Princess Breakfast is better. (See the other threads about CRT and the price increase AND the news that Cinderella will NOT be in the dining room.)
We went to the Princess Breakfast last December and we had such an amazing time! All of the princesses visited our table and spent lots of time with us. We met Snow White, Mulan, Belle, Jasmine, and Aurora. Even my little prince (who celebrated his first birthday at WDW) had a great time! The food was very good and plentiful (they brought refills for our family style platters frequently -- lots of great fresh fruit, which was a hit with the kids!) and we had friendly and efficient wait staff.
We had planned on going to both CRT and the Princess Breakfast during our May 2006 trip but CRT is now off our list. Now we're going to plan on dinner at 1900 Park Fare to see Cinderella and Prince Charming.