I read a "no two anti-virus" rule and I also read about how you can use two anti-virus programs, but you need to do some configuration. Is it worth it to run two anti-virus programs on one system and do some configuration, or is an anti-virus and an anti-malware better than using an antivirus with an antivirus?
Trying to install 2 products which hack deeply into the operating system while doing the same job is unlikely to be a good idea. It's likely that the second will simply displace the first. It's possible that that they may recognize the other's fingerprint database as containing the original malware.
OTOH, for a high security corporate gateway, where the 2 products are running on separate hosts, then yes, it should give better coverage.