SIMtoEXP
For comparison of simulation and experimental scattering data
...Written in C++ and Qt, SIMtoEXP has a very simple and easy to use GUI with interactive plotting. The software was originally developed by Norbert Kucerka.
The code has been tested on OpenSUSE and Ubuntu (both binary and compilation); Windows and Mac are not officially supported, see the 'Notes' in the tar.
PLEASE READ THE WIKI FOR THE MOST UP-TO-DATE INFORMATION - there have been major bug fixes recently.