When comparing ClamXav vs RCDefaultApp, the Slant community recommends RCDefaultApp for most people. In the question“What are the best Mac OSX apps for someone that's new to Apple?” RCDefaultApp is ranked 24th while ClamXav is ranked 28th. The most important reason people chose RCDefaultApp is:
Standard features on Windows, but not on Mac, this fixes that.
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Pros
Pro Monitor directories easily
The Sentry Feature monitors specific directories 24/7 as well as removable media which includes USB & external drives, all those .dmg files you open when installing apps etc. I add all directories that files are downloaded as a "screening" process.
Pro Lean
Not overly invasive or processor hungry as other antivirus programs
Pro Provides missing functionality
Standard features on Windows, but not on Mac, this fixes that.
Cons
Con Does not monitor or protect ram memory
Con Last update was in 2009
But the software still works, so far no issues on El Capitan 10.11.3.