Hi,
It's a lot of work to compare all C++ ORM frameworks !!!
Maybe one day, someone will compare all of them
in release mode (maybe it already exists on a website, I don't know)...
It's very interesting but I have no time to do it
About functionalities, I think QxOrm library provides more features than other libraries (but require Qt and boost frameworks).
About performance, I don't know ! But to test it, be sure to build into release mode
From my point of view, I think the 2 best C++ ORM libraries are : QxOrm and ODB.