I've had UNO for quite a while now and never had any hesitations in repairing permissions. I'm not stuck with it because I can still uninstall it when new releases come out. It's safe.
I've been running Uno for something like a year now with no problems at all. Only when we get a OSX update (10.4.8 to 10.4.9 for example) do I ever get problems, but then they update it pretty quickly. So to answer your question go a head and repair those permissions like crazy.