On my one computer I have an ati 8500aiw and have found myself forced to stick with suse 10.0 instead of 10.1 or 10.2. The 10.1 and 10.2 experiences failed miserably on the GUI end which I believe is related to the xorg version. This has forced me to stick with 10.0 until I replace it with a Nvidia card.

Anyway, I like to keep the system up to date. Yast has always worked good for me with software installs and online updates. The problem that I notice is the installed software versions are not always accurate. One example is, I updated firefox to ver2 and when it is listed in Yast it shows up as ver1 something. This is because I manually updated firefox with a tarball. I have also ran into this with hplip and other programs.

Is there a way to register these updates with Yast or would SMART or APT be a better way to handle it

It is impossible to get YaST or SMART to manage a source based package installation. The better way to handle it is to either (1) find a repo with pre-built RPM's of the versions you need, or (2) make your own RPM with either the normal dev tools (rpmbuild and others), or with the checkinstall program.