I am more and more convinced that you can trust as few or as many AV programs as you want, it makes no difference. In fact, if you don't have any AV software, you probably don't fare any worse. AV software is the real malware, it is what prevents you from working and it is what takes over your computer, making it unusable.
On the other hand, my AV software (different vendors, including the one in this topic) never found a real virus in roughly 29 years of computing and roughly 17 years of being-always-online, which may mean two things: Either I never had one, or the AV software is just useless and doesn't find it.
Now, as to the second possibility, refer to Mr. Porada's well-known live exploit demo on the E-Personalausweis (Nov. 2010) where he claimed none of the scanners at Virustotal raised as much as a warning for his 1-hour trojan, and the AV vendor he working for as consultant at that time was not able to identify it a week after receiving the executable. Of course that trojan was nothing serious, all it did was steal your identity and (more or less undeniably) sign binding contracts in your name, so nothing high priority, really...