Text formats all look the same?
This is expected behavior.

The "Text Format" Select List affects the way drupal parses and displays the data after it has been saved and is being displayed to the end user; not the way it is saved nor the way it is displayed on the Node Edit form.

By default:

Given Input:

&lt;div&gt;
  &lt;h1&gt;Title&lt;/h1&gt;
  &lt;img src="foo.fpg" /&gt;
  &lt;?php echo 'bar'; ?&gt;
&lt;/div&gt;


"PHP Code" filter output

&lt;div&gt;
  &lt;h1&gt;Title&lt;/h1&gt;
  &lt;img src="foo.fpg" /&gt;
  bar
&lt;/div&gt;


"Full HTML" filter output

&lt;div&gt;
  &lt;h1&gt;Title&lt;/h1&gt;
  &lt;img src="foo.fpg" /&gt;
&lt;/div&gt;


"Filtered HTML" filter output

&lt;h1&gt;Title&lt;/h1&gt;