I ordered a Deka EXT30L last week off Ebay, had it in 5 days for $96 and free shipping. Rain stopped today so I swapped the old one out for the new one. The whole job took all of 15 minutes, and that includes cleaning up the battery box. With both batteries sitting side by side, they "appeared" to be the same other than the "HD" logo on the stock unit, and the new Deka having a white case instead of a black one for the stock HD unit. Checked the voltage on the new Deka, and it was 12.7 out of the box. put everything back together and plugged in the battery tender. It charged for about 15 minutes and then went to a "green", fully charged, light. Bike fired off immediately, and with 400cca, I expect no problems for another 4 years.
For the price difference, I see NO reason to give HD that much money just to have a hidden battery with the HD logo on it.
FWIW
Bill