Poll
90%
10%
I'd say Obi-Wan wins. Mara Jade was ok, but she wasn't very good. She just knows a couple of little force tricks, and has used a lightsaber a couple times. Obi-Wan on the other hand is a fully fledged Jedi Knight. He has been practicing the force and using a lightsaber for practically his whole life. He wins.
This is Mara Jade right before the Emperor dies. That means her connection to the force is still heightened, and has plenty of experience under her belt.
But yeah, I still think Obi Wan wins, Obi Wan is just a very good, solid, overall Jedi. Sorry, this is somewhat unbalanced. I'll make a new thread in the future with a more even opponent for Mara.