-The XLR has a more crisper sound
-XLR has more options to adjust audio before recording (with gain and the such)
-XLR has better potential for future customization (mic or interface)
On top of all of this I feel the XLR is just the better investment. Eventually as time goes on I'll probably find myself wanting an XLR setup. No reason in going USB then XLR since that will just run me more money.