I bought a Kindle Fire in November, and I have had a Kindle keyboard for a number of years, so was excited about the Fire. I have to say the battery life compared to the old Kindle is pretty bad, 8 hours as compared to about 6 weeks before needing a recharge. However my purpose in buying the Fire was not just to read, but to watch video's, use the internet, listen to music and various apps that you can install. So if you truly plan on using all the Fire's features, to me its been worth it and I expected the battery life to be comparable to another type of pad, versus just an e-reader.
Plus I find reading on the Fire is easier as its backlit unlike my old Kindle keyboard. However, I must admit to sometimes using my old Kindle for reading purposes. I keep it in my purse and I can read and not worry about having to recharge for about 6 weeks (if I keep the wifi turned off). This is helpful when traveling especially. I can share my books between both my Kindles, so if my Fire is recharging I can get out my old Kindle and continue where I left off.
The Fire only comes with a USB charger, which can take FOREVER to charge up. I found that my old USB to power adapter on my old Kindle also charges the fire, so I didn't have to pay the extra $20 for Amazon's adapter. If you get a Fire, I'd highly suggest investing in a power adapter, the USB recharge time is painful.
So I like the Fire, but its only worth it if it suits your purposes....so good luck with your decision.