I've flown in WBC on both of these planes from SEA
-BOM & return (twice) on DC10s, as well as SEA
on the 330's.
I guess I'm dissenting with the majority here in that I like the A330 better. If you really want to fly in a DC10, you should do it. It is a cool plane and feels very spacious. They still have lots of room (60" seat pitch). However, I've been in DC10 seats where the personal video doesn't work at all (it was fine, I was planning to sleep that leg). But even so, it's a lot less of an offering than the A330's. Basically the DC10 WBC is state of the art 15 years ago, and the A330's are right on par with today's business class. You can see the details of the new world business class offering on NWA.com.
Even though NWA gets a bad rap from a lot of people, I really enjoy flying their WBC. The lounges are decent, vanity kit is pretty complete, and I've found the service to be good, if a little inattentive. You can always go ask for what you need.