I have tested quite a few cartridges on the DV507MKII through the last two years (Koetsu Urushi, DV Te Kaitora Rua, Shelter 90X, Denon DL103, DV XV-1s). Matching step-ups is of great importance with cartridges (far more important than with active units). In my opinion, and in my setup, the XV-1s is the better choice for this arm.
Personally I prefer the combination with a lighter headshell than the original Dynavector (gets to heavy in the bass).