The only major con I can think of is that, because it's written in PHP, if you make a manual edit to one of the theme configuration files (which you probably will end up doing during customization), and have even one minor typo, it will pretty much break the whole site.So, my recommendation is to BACKUP YOUR FILES BEFORE YOU EDIT SOMETHING and make sure you have access, whether it be physical, FTP or cPanel, to your host server.