Avast isn't a bad software, I've used it before. The thing is free antiviruses are quite limited so it's best to maybe get one with a license.
McAfee is okay, I've used it, the only problem I had with it was the constant pop-ups and ads they sent me. It was really annoying and I landed up removing it.
I'm using Thor at the moment and haven't had any issues with it. It's similar to McAfee but doesn't have all the annoying ads and pop-ups.