I noticed Western Digital sells two variants of their 500GB external HD. One labeled Mac, which requires a Mac and their regular passport essential which claims to work on both a Mac and PC. The Mac version is $10 more expsensive. I was hoping someone could point out the major differences and if this $10 price difference is worth purchasing the Mac drive. I linked both products below. http://www.bestbuy.com/site/olspage.jsp?skuId=9258876&type=product&id=1218070096126 http://www.bestbuy.com/site/olspage.jsp?skuId=8993164&type=product&id=1218007082970 Thanks!