General Question About Remembering Property Values Between Postbacks

Here are examples of two different ways I've found to story Property values between postbacks:
    private bool Initialized
    {
      get
      {
        return Convert.ToBoolean(this.Attributes["Initialized"]);
      }

      set
      {
        this.Attributes["Initialized"] = value.ToString();
      }
    }

    private int DataTableRowIndex
    {
      get
      {
        return (int)ViewState["DataTableRowIndex"];
      }
     ...