Spanning sync had worked pretty well in my limited testing, but I couldn't solve the rest of my gCal sync challenge. Without the whole solution Spanning Sync just didn't offer enough.
Time to uninstall. But wait -- how to uninstall? Uninstalling the very best OS X apps is a drag-and-drop operation, but Spanning Sync includes a PrefPane. I started looking for uninstall directions.
At first things looked bad. The Spanning Sync FAQ doesn't mention uninstalling. One blog post suggested the process is pretty ugly. A search on the Spanning Sync site for "uninstall" returned four irrelevant hits.
I downloaded 1.04 again, and that's where I found an uninstaller. It seems to have worked. So they have one, even if they don't document it.
OS X really ought to have an uninstaller, even if most apps can be uninstalled by deleting them. (Though apps typically leave support data scattered around, you can use spotlight to find them. In the case of an app like Spanning Sync, you need to switch to each user's account and run a search if you want a full cleanup.)
Update 9/4/08: The iPhone made me a Spanning Sync customer after all. Meanwhile, a year or so after I posted this, Spanning Sync finally added a note to their FAQ about uninstalling. I'm glad they relented, but why did that take a year?