I tried it for a while a few years ago but it gave me so many activity reports (none of which I understood) that I gave up. My computer's still fine so it must have been reporting normal activity. It may well have been that I'd not set it up properly and of course it will have changed over the intervening years so may be a much better prospect now.
I have have it and it runs quietly in the background but prompts you to allow access to new connection and you can take a look at what you are connecting to. I have on occasions blocked a connection but mostly allow connections for duration if not essential for day to day operation. I don't really understand the finer arts but enjoy having it there.
Mark Ford 