There are a number of antivirus software available in the market and all of them have different detection rates, different update cycles and many other factors driving their popularity. But there are issues which we often ignore.

These can be the overhead when the antivirus detects a virus, the time required by the antivirus to remove a virus and the amount of resources it needs to do all this.
According to me, the most important one of these is the response time. An Antivirus with a good response time will have a better detection capacity and effectiveness. This time can be checked with a small method.
This is called the EICAR  test. EICAR is the European Institute For Computer Antivirus Research. At the research facility, they have devised a test string for antiviruses. The test string is :

X5O!P%@AP[4PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*

All you need to do is copy the text into a file and save the file as a .com file. The file is a Windows executable and simply displays “EICAR-STANDARD-ANTIVIRUS-TEST-FILE!” on running. This is a perfect example of self modifying code. Your antivirus should detect it as a virus immediately.
I primarily use Avira Antivir. Most of the other antivirus software I tested, fared well to the response test.