We agree with everyone, from the UK our DD is coming for her third trip this November and has been at 8 months 29 months and 34 months soon! Also
Disneyland Paris when she was 18 months.
Some might call that obsessive

but the main reason is that flights are cheap out of school holidays and we are now DVC members (and the dollar is good for us)
More than that is how much she loves the characters, we have photos of her refusing to let Chip and Dale go at 8 months old accompanied by a high pitch squeal of delight. I am not good enough with words, that or they don't exist to explain just how much she enjoys it. If they bottled joy then it would be made by families like us in Disney.
I am usually cynical and have a hard job in IT outsourcing and I walk on cloud nine for however long we are out there high on how much she is having fun and the wonder in her face at just everything. A cast member in DS commenting on how she was even hugging the trees outside the Narnia exhibit.
Try local theme parks or events with people in costumes or dressed up to see how they react. My nephews before my daughter arrived went to Paris and cowered in fear all the way through a character breakfast so anything you can do to work out if it is for them before hand will save you money and disappointment.
My wife has just pointed out that another reason we love vacationing in Orlando is quality of food, medical assistance (which we have had to use) and ease of buying baby / toddler necessities. You can't find anywhere more geared for family holidays.