So I ordered a Fire TV pretty much as soon as the order page went up from Amazon after the reveal. It has since joined our Apple TV, Google Chromecast and PS3 on our living room TV.
The Good:
Amazon was not kidding about it being fast. I wouldn't say it is night and day compared to the Apple TV but it is very noticeable. Especially when going back to the Apple TV after using Fire consistently for a few days. Load times are extremely rare.
The best part about the Fire in comparison to the Apple TV for us has definitely been the improvement with the remote. I now hesitate to deal with the Apple TV interface unless I do not have an alternative on the Fire. This has cost Apple sales from me as I now buy on Amazon first and iTunes second for video content. I know Jobs had a fetish about reducing buttons. But the Apple TV remote control has gone to far in the minimalist direction. It also really should go to a bluetooth or wifi based connection with the device. The fact TVs have not generally adopted a remote control solutions using bluetooth or some other non-line of site solution in place of IR as a standard is beyond me. Why apple went IR with their hobby and have yet to update it is a source of much head scratching. Of course we still try and point it most times... some behaviors are hard to unlearn.
The So So:
The voice search capability is a tease. For the content it covers it is awesome and the recognition/speed is very impressive. However, the lack of integrated search across multiple streaming apps like Netflix and Hulu in addition to Amazon's own content is very frustrating.
The Interface. In comparison I'd say the fire interface is on par with Apple TV... but that is damning with faint praise. It puts your stuff on screen to scroll through in various pre-determined categories. Big miss in that there is no ability to easily limit search results to prime. Confusing also because Prime playback in some cases will have a price tag even if you get it via Prime for no cost. Look for the "prime" banner on the content thumbnail. As long as it is there you are ok. Also if you keep your PIN required for purchases you cannot accidentally get charged.
Games. I got the controller and I have tried some titles. The best I encountered by far was the Walking dead title. basically because it plays like a show and requires mostly decision making than button mashing. Some of the more action based titles I tried were not so hot. Limited device storage makes more complex but significantly large games like Grand Theft Auto 4 problematic. For basic puzzle games I am sure it works great. But it is not really a playstation/xbox substitute that is for sure. Expect gen 2 of this device to address some of this. The potential for this capability is high, execution is still lacking though. Potentially fatally hamstrung by the device limitations though.
The Bad:
Lack of storage. Mostly this is only an issue with games. Streaming may solve this in the future, but the implementation here really isn't there yet. Putting it here because they definitely upsold the gaming capability, but in reality the anemic storage hamstrings the capability right off the bat sans a solid game streaming solution.
Lack of integrated search. First device where I can do a search that returns all options available for me to watch covering free,rental (with cost),Purchase (with cost) that launches the show/movie directly from the search results in whatever capability has it will probably see me unhook other options.
Lack of open connectivity with non fire devices for stuff like screen casting etc... One of the primary uses our Apple TV still gets is casting video via airplay from an iPhone or iPad. Amazon could have supported chrome cast for iOS and Android devices and still had a more powerful second screen capability exclusively for its fire devices. This is a silly and greedy limitation which ultimately alienates any customer that doesn't buy into their complete device ecosystem. Considering the recent release of their phone it is possible they have delusions of being able to present a serious challenge to the iOS/Android eco systems. But they have a LONG way to go.
Wrap Up:
This is a very solid device. On balance I like it considerably more than the Apple TV but we have too much iOS/iTunes inertia in our house to retire it. For anyone looking into an internet set top box I recommend it. Especially if you are already invested in Amazon online video content or otherwise uncommitted to iTunes or Google Play content. I know at launch purchase of one of these also got you either an extension on your Prime membership, or granted you prime membership for a year. If that is still the case and you use Amazon for any shopping needs it is a no brainer.