If it was a brand new boat or only a few years old, I might be more enclined to take to the dealer for repairs/winterization. In fact, I've been winterizing my 94' at the Bu' dealer for several years but just this year, decided to do it myself. My dealer was pushing $400 with all the fluid changes so I decided to try it all myself. Turned out great (so far.....we'll see next spring if I missed something
Just depends on your comfort level.
However, your $700 is Canadian dollars too (I assume) so that needs to be considered too when we (down in the US) compare your winterization cost. Also, what's in that price?