I`ve fired quite a few at it and generally it has come up well, obviously it has missed a few (mainly fake av`s) but no AV catches everything.
The scheduled scan is just a quick scan and can be done whenever, also there is an option to scan all downloaded files and attachments. I wouldn`t wan`t an AV to scan emails anyway the can corrupt them.
Been using it since Beta/Morro and not found any major issues, hopefully this will stop a lot of p.c`s becoming infected...
Paul Thurrott does a pretty good review of it HERE