classic and hot dogger are pretty much the same boot, except for 2 things (at least with those two) The 09 Hot Dogger (purple zebras) have a #4 Flex and an Active Boot Board while the 2010 Classics (Black and Green) has a #6 Flex and a Rigid Boot Board.
So it's basically between softer flex with some shock absorption or stiffer flex with more feel for the snow.