ref object or object with ref field

[mratsim]

Is there any performance/memory/anything else tradeoffs I should be aware of 
between those two type declarations? (note the place of the ref)
    
    
    type
      Context*[T] = object
        nodes: ref seq[Node[T]]
    

And
    
    
    type
      Context*[T] = ref object
        nodes: seq[Node[T]]