Question

From what I gather the following two will bring back the same result

FB.api

FB.api('/'+user_id, function(response){
   document.getElementById('name').innerHTML = 'Your name is ' + respone.name;
});

FB.Data.Query

var query = FB.Data.query('select name, uid from user where uid={0}',user_id);
query.wait(function(rows) {
  document.getElementById('name').innerHTML =
  'Your name is ' + rows[0].name;
});

So what is the difference between these two, what case would one be preferable over the other?

Answer 1

From the docs,

FB.api makes API calls to the Graph API or Deprecated REST API.

FB.Data.Query performs a parameterized FQL query and returns a FB.Data.query object which can be waited on for the asynchronously fetched data.

Basically you can use FB.Data.Query when you want to perform some kind of an advanced query using FQL. Read more here.