Got an invite back at the end of December and ordered on New Years. They missed the shipping estimate, gave me $10, then got it to me two days later. Between the CC points, Prime, and the $10, got it for around $72.
So far, very pleased with it a bit over a month in. We have a ranch and it sits in the central hallway, closer to the kitchen and living room.
Music from Amazon Prime (can add songs/albums/playlists to your library, as well), TuneIn, and iHeartRadio, plus direct Bluetooth playback (can control things like Spotify as well) from mobile devices.
Timers/alarms, weather, news, are all pretty basic but effective. Coin toss - handy. Having the different forms of input is nice -- the voice control is really good, but the remote is handy (have it on the fridge, usually just tap next track or hit the volume button now and then), the app on the Kindle tablet, and I can access it from my Windows Phone through the browser...over LTE. Not even restricted to being on the same wifi network.
The kids were weirded out for about two days. The wife was challenged by her new tubular rival and refused to speak to her. Then she didn't believe that a timer was actually still going, and I told her to just ask about it. Boom "two minutes and forty seconds", evidently I did a terrible job not smirking.
The real test is whether Amazon has the stomach to stick with this and keep developing it. We will see -- have an original Kindle Fire as well that doesn't exactly inspire confidence in that department. Just got an email today though -- they are developing an SDK for it. If they can open it up to have as much flow through it as possible, well it will be more useful to me, and more useful to them. I'm okay with that arrangement...
Finally, completely hands free voice control is totally spoiling me. Little things like wanting to turn the TV off with voice control. And then the last few weeks of freezing cold have left me going out to the car and wanting to talk to my key fob and say "Alexa*, come pick me up at the front door."
*that, or KITT