I think it's a worthwhile purchase unless you already have an iPad. For first-time tablet or eBook reader buyers, this is a no-brainer at $199.00. The only real downside I really see compared to the e-ink versions is the shorter battery life. During the power outage brought about by the recent typhoon, I managed to finish two books on my Kindle.
But hey, 8 hours for the Kindle Fire is still a long time and you get to enjoy nice colored publications like magazines and comics. You can play videos and surf the internet with the fast Silk browser. And heaven forbid, open Office documents.