I can't comment on importing a boat into the U.S. (I live in Ontario) but importing into Canada from the U.S. isn't difficult, particularly for a boat built in a NAFTA country. If you buy through a broker you will be charged the 5% G.S.T. but if the boat is exported to the U.S. you can get a rebate. If you do go this route, ask the broker about the details and where to get the appropriate forms.
Provincial sales tax (8% in Ontario) will also apply but I don't know the procedure for either getting a rebate or avoiding this tax on a boat for export. Again, bring this up with the broker and check with both New York and Ontario regarding this issue. A privately bought boat isn't subject to G.S.T and the provincial government only gets you when you license your boat in Canada so you should be OK on the P.S.T. issue.
As S.Dog mentioned, the Canadian dollar isn't working in your favour although I wouldn't be surprised to see the value of local boats dropping somewhat to be competitive with boats in the U.S. Cross border shopping is a big issue here and where Canadian prices are higher than the U.S., expect to see heavy traffic across the Peace Bridge to Buffalo.