At the Smugmug power and pro levels, what are the main feature differences between Smugmug and Zenfolio?
For context here, I'm currently a Smugmug customer. I'm not anticipating a change to Zenfolio, but I get asked all the time about which service is a better fit and what the actual feature differences are between Smugmug and Zenfolio so I'd like to be better educated on those feature differences and when one service is a better fit for a user vs. the other.
In addition to general feature differences, I'd also like to know if there are any substantive differences in the ability to customize the site and in site performance and if people trying to make a business out of selling photos find important feature differences between the two?
Please do not respond with which site you like as this is not a call for opinions. We're looking for factual differences and how those differences matter to various types of users.