What are the differences between the 2? Is it just the taller deck on the SS? Is the bottom same?

The SS (Newer Hull) has a step and the Dominator does not. Less freeboard on the Dominator also.

I'm new to the SSR hull but part of the difference is the ventilated hull versus the twin step. BO-G has a SS and will likely chime in but the SS has the same hull but not sure about the cabin. I came from a 06 288 which has the revised true step but the freeboard difference between my SSR and the 288 is HUGE. Most 05 and older 32s had the ventilated hull and the lower freeboard.

Also, mine is still considered a SSR Dominator and I know along the way it was called a SS model/hull design. They're changing up the marketing so it's a little more clearly stated.

The S, SS, and SSR are basically just different trim levels of the boat. They all have the same hull. S models are stripped down with a more basic cabin. The SS is the base model of the boat with the deluxe cabin. The SSR is the more dressed up version with more options and custom added "bling" items. The old Dominator had less free board and did not have a fully enclosed head. The newer models have an enclosed head and more head room in the cabin.

The older ones sit lower in the water because of the less freeboard, some like the look more (I do) and some don't. The bottom is also a straight V, there are no steps. Marginally smoother ride at the expense of a few MPH.

Really, you can't go wrong with either. Buy whatever boat is in the best shape and is the best deal! You'll be happy for sure.