How good is Avast antivirus software?

Well Kaspersky rates number one in almost all tests with a detection rate of about 99.7%. Occasionally NOD32 beats it out for first place. Norton ranks at about 92%, but really slows your system to a crawl and often causes more problems than it fixes. Avast rates at 80% and AVG has about a 72% if I remember correctly. In my experience both Norton and McAfee have a habit of finding viruses but not being able to fix them. I've never had a problem removing viruses when Avast finds them. I've been using Avast on all my computers for years and haven't had any problems. I also use it to fix other people's computers since it include a boot scanner that will scan even protected areas of your hard drive before Windows starts.