I find security in understanding how best to secure a browser, rather than
switching to whichever one advertises the least vulnerabilities regardless
of how open that interpretation might be.
My point is that crunching numbers reveals different results, depending
solely on the desired outcome. One could equally argue that Firefox had the
advantage of learning from IE's mistakes, hence comparing the first six
months of a browser three years later becomes a moot point. But, of course,
if one were to make that argument, one would expect Firefox to have done
better in the previous six months, which it clearly has not.