You could get good discounts from some Harley dealers a few years ago, then Harley forced the dealers who were selling ESP's out of their market area to cease and desist. Harley hates to see customers get a good deal on anything. If you want the plan endorsed and promoted by Harley, you are stuck with the prices the various dealers charge in your area.
As others have noted, check out the other company's ESP offerings. Do some research not only on price, but look for customer reviews to gauge how well they respond to claims. Also see what shops in your area accept direct payment from those plans, versus you having to pay up front and submit a claim yourself. And be aware, even with the Harley endorsed plan from CNA, you aren't limited to just Harley dealerships. You can take the bike to any shop, even independents. Ask for a complete copy of the contract so you can check actual coverage and any gotcha's in the fine print before you sign on the dotted line.
JMHO - Jerry