There are some other threads on this topic in the forum that have some relevant posts - you should be able to find some good thoughts there.
Also, CanadianMortgageTrends website is a great resource for all things mortgage. I'm pretty sure they've got some analysis on the topic over there.
I did break my mortgage recently, and early-renewed with the same lender. I may have jumped the gun just a little bit and could probably have done better today, but when we are talking about 10ths of a point when rates are at 4%, I feel fortunate to be able to be paying down a mortgage today.