Viruses are well tested before their release - all the time! Do we see viruses crippled due to internal bugs?
IMO, 'heuristic detection' shall always remain a joke if virus makers test their work against a/v products, and of course they do - you don't often see your a/v product pops up a message box that says "unknown virus/malware - cleaned", do you?
Well, I don't think those popular a/v products sometimes suck simply because they're market leaders; new viruses emerge and go wild undetected everyday because they are new and unknown.
Large anti-virus companies generally are more willing and able to put more resources into hunting new viruses and update their products, and of course, to fund the R&D of more advanced engines. This gives them a better edge against the less popular vendors. For many of those small vendors, they might not even get aware of new malware until popular vendors update their virus encyclopedias. The more vigilant and responsive your a/v product vendor is, the less vulnerable your system is.
80 percent miss rate
actually it talks about 80 percent of new malware
, which might be a gross underestimation, if you define 'new' as 'within a week of first discovery/detection by someone'. AFAIK, none of those mentioned popular a/v products are good at detecting/eliminating new malware (actually they are most often blind and deaf even with up-to-the-hour patches.)
My suggestion is to install one or more anti-spyware products (best with real-time detection) in couple with your existing anti-virus program.
Nothing kills new
malware - if they are new enough.