I believe the only difference is that the free one has ads. I get an ad after every word I play. It's no big deal to me. If there are any other differences that anyone else knows of, I'm interested, too!
I have the paid for version on my iPad and the free version on my iPhonen the only difference I see is the ad after every word played on the free version.
I'm up for a game and I lose as many as I win. You can find me as Aledomom.
I played for a while with the free version, but the ads got on my nerves so I paid for the regular version. I'm enjoying the games with my new Disboards friends!