The DV model predated the XL/XLD and SL/SLD series models. The DV became the SLD a couple years after the XL series was introduced when the seating was reconfigured, adding a portside bench seat for up to three people.
DV - 21 degree deadrise and seating for 2 in cabin. Notch or bracket.
SLD - 21 degree deadrise and portside bench in cabin for more seating. Notch only.
XLD - 21 degree deadrise and inward facing rear jump seats. Bracket only.
There are other finish and feature differences but they are fairly minor other than the XLD having a solid bulkhead with door separating the helm from the berth area and a shallower step down into the cabin from the cockpit due to the taller XL cabin.