Please consider changing Photo Mechanic's XML export format. The present format is:
<key>file_size</key>
<string>18.7MB</string>
<key>date</key>
<string>4/12/2008</string>
<key>time</key>
<string>2:44:00 PM</string>
But this kind of generic tagging scheme, with the content of each "key" describing the purpose of the next "string" in the XML file, doesn't do what XML tagging was designed to do: unambiguously describe the nature or purpose of a discrete piece of data. XML elements should be specific kinds of containers, as it were. For example:
<fileSize>18.7MB</fileSize>
<date>4/12/2008</date>
<!-- Please use ISO date format if possible: 2008-04-12 -->
<time>2:44:00 PM</time>
And/or, use attributes for unambiguous description:
<IPTC_FIELDS
City="Stockholm"
Country="Sweden"
Keywords="comma-separated keyword list goes here"
/>
or
<IPTC_FIELDS>
<city>Stockholm</city>
<country>Sweden</country>
... etc.etc.
</IPTC_FIELDS>
The XML file certainly needn't be as grim-looking as XMP, but surely it should be far more XML-like than it is at the moment.
Other things I noticed about the XML-export feature: it doesn't write a final carriage-return+line-feed to the file, something that a few text-processing utilities will interpret as meaning that the output file isn't an actual text file. If the user-named XML output file already exists, there is no overwrite warning. If the output file exists but is unwriteable for some reason, PM doesn't exactly crash, but it does present a runtime-error dialog that appears after the program has tried to write to the output file. The dialog box is probably useful for diagnostic purposes ("(eval):642:in `kickoff_background_export') but requires some guesswork by the user to determine what went wrong.
Thanks.