Good:

1. Impossible not to mention the price first. At $200, it is an easy recommendation to those interested in buying a tablet but hesitant of a $500 plus price tag. And it cannot be understated, the Kindle Fire is a very good (not perfect) iPad substitute.
2. Amazon.com and cloud integration is seamless. Apart from the price tag, this is easily the biggest selling point. Once registered, all Kindle books, magazines, applications, Amazon instant video and MP3s sync immediately.
3. Bright, color rich screen. Decent built-in audio. It's small and lightweight, yet sturdy.

Unsure:

1. The Amazon Silk web browser is fast, but the quality of a particular page is really inconsistent. Having the ability to tab browse is awesome, but it would be nice to be able to view websites and internet video in a landscape mode. This could possibly be corrected with a firmware update.
2. The battery life is about 7 or so hours. In this price range, it is neither good nor bad. For how I use the device, it is more than acceptable.
3. No access to the Android application marketplace. This might be a bigger deal at launch, but the Amazon app store will grow rapidly to the point of it being irrelevant.

Bad:

1. No 3G support and only 8 gigabytes of on device storage. As impressive as the Amazon Cloud is, it is moot if you can't communicate with it. For times when you don't have access to wifi, this could be a legitimate pain.
2. No camera, bluetooth. Cameras are nice, though not a necessity. Bluetooth is a bigger deal with regard to making edits to documents with the virtual keyboard.
3. It doesn't have that Apple polish. The Kindle Fire suffers from a little bit of first generation "jankiness". This will be a bigger deal to some than others. In most cases, it's form of function. But it's hard to rival the sleekness of the iPad, and the Fire falls short.

Conclusion: Buy it if you are either heavily invested in the Amazon cloud with your Kindle and MP3 library (and if you have a Prime account for streaming video), or are looking for a cheap alternative to the iPad. Don't buy it if you want a top of the line tablet with a fully established application store and/or if wifi isn't readily available in your daily life. It's not an iPad killer, but it's a legit competitor. It will do well in expanding the tablet market, which I think we can all agree is the healthiest of predicaments.