I agree... I have been on the beta versions of Lion for a few months now and the GM build just recently, which is the same build number as the final retail version, and Espionage definitely has some bugs that need to be worked out. Primarily for me, it does not auto-unlock data folders all the time when it is selected to do so and often gives errors when trying or makes the app bounce non-stop in the Dock as it can not access its data. Sometimes I can not shut the bouncing app down as it is not really running, so I have to wait for it to eventually give up and just quit bouncing. It definitely does not auto-lock those data folders when you quit the app. There are other quirks, but as long as I manually unlock those folders from the icon in the menu bar before launching the app, it is fine, I just have to remember to also lock them again manually from the menu bar icon when I close them again, because quitting an app that is set to auto-lock its folders on exit will produce an error from Espionage saying it could not lock the folders.
If you are worried, I would wait for them to release an Espionage update before upgrading to Lion.