I always transfer to a carboy. I don't think that it matters a whole lot. The advantage is to get all the trub out of the beer which makes it easier to bottle a clearer, less silty beer.
2 weeks in the secondary is a safe amount of time to leave the beer so the fermenting is all done. You can likely bottle it sooner if the specific gravity remains constant for 2-3 days. You'd need a hydrometer to determine that.