Read this EE Times article authored by Harry Foster.
Harry elaborates on his formal verification and assertion-based verification views.
"Granted, I live and breathe verification methodologies in general, and I am particularly fond of formal verification. And the old saw does hold true: when you have a hammer, everything looks like a nail, or in my case, like an opportunity for model checking or mathematical reasoning. Still, on second glance at the survey, I see lots of reason for optimism."
Read the entire article.