phpSniff does not correctly identify the new Intel-based macs which have a different identification in the HTTP_USER_AGENT system variable.
In the file phpSniff.core.php...
Update the regex string on line 243 from:
$regex_mac = '/(68[k0]{1,3})|(ppc mac os x)|([p\S]{1,5}pc)|(darwin)/i';
To:
$regex_mac = '/(68[k0]{1,3})|(Macintosh)|(ppc mac os x)|([p\S]{1,5}pc)|(darwin)/i';
Adding...
2006-11-20 06:20:04 UTC in PHP Client Sniffer