I've done a test to find out. I took a full datapump export of a 9.5GB database followed by an old-style export.
The results are pretty conclusive, but obviously for a better test you should do more databases, different sizes and different options:
DataPump - started at 15:12:00, finished at 15:41:34, so elapsed time was 29 mins and 34 secs
Export - started at 09:32:56 and finished at 10:27:26, so elapsed time was 54 mins and 30 secs
Later on I'll do an Import and post the results.
