I am using it from 2 years and in the middle I installed many antivirus softwares like norton, avg, avast, kaspersky, and others.but quick heal rocks.
It detects every thing and very fast.even if some virus is not there in its database it will detect it due to the DNA scan feature it is having. as soon as you insert any device like dvd or pen drive which is having virus, it will detect it and block that file.i compared it with others.there was a virus in my pen drive and norton did not even detected it.avast detected the virus but it could not stop it.
Quick heal detected it very fast and stopped it from running.it was using almost 75 percent of my cpu usage although I am having a quad core processor. I used kaspersky also.it is also good but slows down the system, (the newer versions are very good).as it is not having dna scan, there is no use of it without updating it regularly.