DataType vs UiHint

I have been using mvc2 for a while now, and when i need to set the template i use the DataType Attribute

    [DataType("DropDown")]
    public int Field { get; set; }

I see others using UiHint to achieve the same results

    [UiHint("DropDown")]
    public int Field { get; set; }

What is the difference between using these two attributes? Which attribute should I be normally using, or are they for different tasks?