Ranked in these QuestionsQuestion Ranking
Pro Comes bundled with all Windows versions by default
There's no need to set up the tool, it comes with all versions of Windows and as long as you install important Patch Tuesdays updates the tool will be up to date.
Con Doesn't scan the whole system
The tool checks for just the most common infections and only in the most common places and skips everything else.
Con Runs only once a month
The tool automatically runs after each "Patch Tuesday" patch has been installed. And there's no way to have in scheduled to run more often. To run it at any other time it has to be done manually.
Con Can't scan in the background
When manually invoked, there's no way to have it run in the background.