Oh yeah, symantec does a fantastic job. *sarcasm* No software is bulletproof. That includes linux and unix. The only reason they aren't being attacked as much as microsoft is because they aren't in the headlights of the public. When i see microsoft trying to develop anti-malware software I'm happy to see them actually trying to lay down some preventative measures. Remember when those viruses were released for OSX. It took apple almost three quarters of a year to come out with the patches. At least I see microsoft making an effort.
As for being competition for other malware scanners, I say its a good thing. Competition means a higher grade of product. Maybe if microsoft gets in the game symantic will get its s**t together.