The HVX200A does not have the HD-SDI interface, but has the Tape Drive so it can also be used as a DV camera.
I look at the products as being primarily equal but they have differences that would make them ideal for the target customer. The 200 would appeal to the person that still has a lot of DV based customers. The 170 would appeal to the person that is sold on the P2 workflow and wants a smaller camera that offers HD resording. The 170 also offers the HD-SDI output so it could also be used in a live output scenario.
Hope that helps,
Jan Crittenden Livingston
Product Manager, HPX500, HVX200, DVX100
Panasonic Broadcast & TV Systems