IBM / ISS released (partially redacted) security advisories against Trend Micro. I think John Pescatore got it right in this article:
These kinds of competitive rivalries really bring out the worst in security companies and highlight the house of cards that is vulnerability discovery and disclosure. Perhaps more importantly, you'd think ISS would act differently given its experience with the Witty worm and its somewhat strange circumstances... although they may hold the record for the number of vulnerabilities found in competitor products (hmm, maybe I am confusing cause and effect here).
In any case, I doubt it would pass my litmus test. I really don't understand why the profession facilitates arbitrary target practice. Pescatore cuts to the chase with his IBM point, and I am tempted to challenge for ISS to out IBM sometime soon, except that it would increase risk. In any case, IBM would be a target-rich environment in an arbitrary world.