.plist returns: Invalid property list, plutil says ok!
Because it would be more difficult to post this in a comment I'm posting it as an answer, although it may not be the right one.

I took your command line while using Lingon X to create the .plist file, here is how it parsed the command line, which is different from yours.



&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"&gt;
&lt;plist version="1.0"&gt;
&lt;dict&gt;
    &lt;key&gt;Label&lt;/key&gt;
    &lt;string&gt;name&lt;/string&gt;
    &lt;key&gt;ProgramArguments&lt;/key&gt;
    &lt;array&gt;
        &lt;string&gt;sshfs&lt;/string&gt;
        &lt;string&gt;-o&lt;/string&gt;
        &lt;string&gt;allow_other,defer_permissions&lt;/string&gt;
        &lt;string&gt;user@xxx.xxx.xxx.xxx:/home/user/&lt;/string&gt;
        &lt;string&gt;/Users/user/Desktop/Website/&lt;/string&gt;
        &lt;string&gt;-o&lt;/string&gt;
        &lt;string&gt;reconnect&lt;/string&gt;
    &lt;/array&gt;
    &lt;key&gt;RunAtLoad&lt;/key&gt;
    &lt;true/&gt;
&lt;/dict&gt;
&lt;/plist&gt;




You'll note that while I used the command line you have in your question it didn't include the path to sshfs, you might have to add that back. The other thing it did different is each string in the array holds the information up to but not including the spaces between the arguments.  Maybe this makes a difference.  Can't say since I can't test your command line however it's worth a try using the format Lingon X created.