Building websites with Elegant Themes is really nice. I use to optimize a lot the themes, therefore I nearly always create a child theme, but this remains easy, and the themes are well structured and well documented.
I made websites like this one,
a hotel in Morocco that uses WPML and was slightly customized, or this one
for expatriates in Morocco, which had been heavily customized, with some custom post types, custom taxonomy, google maps and integration with MailChimp and Gravity Forms... and it was a piece of cake
