Avast is great on Windows but on my Mac it was so obtrusive, asking me for every connection (disabled due to Little Snitch) and warning me my mail was encrypted (which I couldn't find a work around). In the end I uninstalled Avast after one day of non-stop nuisance pop-ups. They need to make it work more seamlessly and less obtrusively (e.g. it needs to be more intelligent).

I've used the Windows version for some time without problems including an install via Parallels on this Mac, so I was curious to try this out on OS X.

To my surprise it turned my 8 Core Mac Pro with 32 gigs of Ram into a horribly slow, unresponsive mess with frequent spinning ball and that doesn't happen even when I'm running several resource hungry apps like Photoshop and Lightroom at the same time on heavy tasks.

I looked inside the activity monitor for clues but couldn't see anything obviously wrong, yet it was patently clear from the sudden slow down while Avast was running a scan that something was wrong, so I uninstalled it and normal service resumed. I've not seen problems like this in the past when trying Sophos or Clamav.

Not trying to advocate antivirus programs on the Mac but if you're the paranoid type then this is the best option for you. It's light on system resources and is very accurate at detecting malware. I can't give it 5 stars as it's still in beta but that can change in the future.

Works good so far.

Only nuisance is setting up the mail server proxy to intercept mail traffic. As far as I've seen, Apple Mail has to be set to not use SSL, because the Avast shield does that.

If you don't switch off SSL, you'll end up with numerous on screen warnings.

Hope this has been worked around in the final version.

Avast has an outstanding free version for Windows.

As there are existing proven free alternatives (ClamXav and Sophos) for the Mac, I see absolutely no reason to get into a subscription fee BETA.