It creates a powerful incentive not to disclose vulnerabilities within a large window of time preceding CanSecWest (disclose now: $0; disclose in March: $15,000), and it creates false perceptions about the relative security of browsers and about security in general.

The argument against Pwn2Own is pretty straightforward.

Incidentally, switching from IE for security is tricky. There are some (v. popular) browsers you could switch from IE to that (the C.W. says) would make you more secure; others, less. The IE family has a lot of problems, but "owned by people who don't give a shit about security" isn't one of them.