PHP evaluation for "Send HTML email body"
If field_software_product_sku is text field you should test on value of the field something like:

if ($node-&gt;field_software_product_sku[LANGUAGE_NONE][0]['value'] === "Some Product Name"){
    echo "&lt;a href=\"http://www.mywebsite.com/Some Product Name/some.exe\"&gt;Trial Version Download Link&lt;/a&gt;&lt;br /&gt;";
  }


other ways if it doesn't work, i suggest you to use Devel Module and dump the $node-&gt;field_software_product_sku using dpm function to see the value of the field:
dpm($node-&gt;field_software_product_sku) and then check on the value of the field.