We had implimented the Outlook 120dpi fix but this has caused us some problems on iOS8 and 9. If you placed the fix (see below) into the <head> tag if it wasnt above the style tag it would display "96" in the email description in the email app. Move it below the style tag and it displays nothing "message has no content" if your title tag is empty or the contents of you title tag if its not blank. The email renders properly in all cases.

<!--[if gte mso 9]>
<xml>
<o:OfficeDocumentSettings>
<o:AllowPNG/>
<o:PixelsPerInch>96</o:PixelsPerInch>
</o:OfficeDocumentSettings>
</xml>
<![endif]-->

I'm aware we could just use the same copy in the pre-header in the title tag but there must be a better way.