Hi Harry! Having a stable machine does beat the alternatives :) , but there is very little in the way of behavioral testing folks have done outside of larger institutions with workflow-driven apps like eggplant or sikuli script (I know a company that makes the internets had built arduino bots to literally plug stuff in and press keys or something, even.)
Beyond specific apps and workflow the image will support, a tip-off would be network interfaces or other hardware features not being as they should. Another random note, oddly enough I had an issue that a cleanly-installed 10.8.3 didn't have certain drivers for FinalCutX to preview canned audio clips while editing(though it would play when added to the scene, and no other symptoms were noticed.) I should've filed a bug report, the combo updater included it… maybe it was fixed in 10.8.4, I don't have access to the systems anymore.
Allister