In off-peak times (like, mid-day) I will mix/match either taking the Resort Monorail from the Poly station or walking over to the TTC to take the Express Monorail or Ferry. BUT, I don't like the TTC option during peak times, especially mornings and when leaving the MK after fireworks - just not worth it to have to deal with/blend in to the larger crowds. For AMs and anything near fireworks, my choice is always Resort Monorail at the Poly station or the Poly resort boat... at other times I'll just go with the mood.
Hope that helps!