Are there nowadays circumstances where you'd better use radeonhd instead of radeon? I think not, if I read this from the Xorg radeonhd wiki:
- Status 09/2010: Linux distributions, including Novell's openSUSE, have now abandoned radeonhd as the default driver, instead using the radeon driver. radeon has more features, including Kernel Mode-Setting support and more 3D support, and it supports all Radeon generation from original R100 Radeons to R800 Radeons (HD 5000 series). Radeonhd can be continued to be updated as long as there are people find it useful.
If not, my suggestion would be to archive this page and to delete links from the other AMD graphical hardware articles to this radeonhd article. -akaper