I've had the Kindle Fire for only a little while now and these observations are those made in playing with it for a couple hours, tops.
Initial Impression: It's heavy, MUCH heavier than either the Kindle2 or the Kindle Keyboard that I had. But it feels solid, well built. There are zero buttons for controlling the thing outside of the power button. I plugged it and it ran an update and knew my account. It arrived pre-set up with my account information. That was nice. It was ready to go within minutes of taking it out of the box.
I was able to send a book to myself using the @kindle.com e-mail address through the Manage My Kindle pretty easily. I also was able to deposit home-brew copies of books into the books directory and they were there and as easy to read as if they'd been bought through Amazon. For reading getting to my books to use as an e-reader it was fine.
The speakers are at the top, not the top facing me, but the very top, facing straight up. That didn't seem to bug me when it came to listening to music. There's enough separation for the stereo to be noticeable in stereo songs and it streamed stuff from my amazon cloud collection pretty easily. The player is nice and all the controls I needed were accessible without having to monkey around in menus.
I synced up my Netflix account with it and watched part of a Doctor Who episode and can see myself watching more without much difficulty. The case I got folds to give it a nice stand. It's playing right now while I type this. I put a copy of _Do You Want To Date My Avatar_ in .m4v and a copy of an mp4 on there as well, _Not Afraid_ by Eminem to see how those formats worked. They worked great, but they weren't immediately obvious where to find them. They're in the Gallery, and not in the Movies tab across the top.
There's a built in Gallery for viewing photos and evidently videos added by USB. The drawback here is it doesn't show the name under the thumbnail and the thumbnails were pretty small for the videos. The playback is good though, very smooth. Viewing pictures was just like using the gallery in an android phone, just swipe past them. There's no "share" option showing up other than Evernote though and I'm not sure why I'd want to do that. (I had to add Evernote... without it the Share menu would be empty I assume.) There's no option to make the wallpaper one of your photos which is frustrating.
This is where things go weird for me.
This is an e-reader. This is *NOT* an iPad. If you think it's a cheap iPad you're going to want to send it back unopened. You will be disappointed. The App selection is VERY limited. Angry Birds worked great, relax. But so far there's no Dropbox support and no gmail support other than through the web browser (which was quick and clean and I used it for both gmail and google+ and it was fine.) I knew I wasn't getting a dumb tablet, but a smart e-reader, but I'd hoped for a gmail app. That was a thing I was really counting on using this for and it's not there yet.
I'm not a super-fan of the interface. The home screen has your four favorite (You pick what you want, it starts out with 4 by default, but they're easily changed) things to do. They can be books, songs, albums, apps, bookmarks, whatever. Then above your 4 favorites is this carousel they call it where everything you do is in order one behind the order going back in time. Looking at mine now I can see I Used the Gallery, Played 90 Seconds to Mars album "This is War", read some of Storm of Swords, used the Comixology App to read a comic, played Angry Birds, and then I see I was on Google+. I hate that. I want the home screen to be customizable, not a breadcrumb trail of what I've done. Across the top are the sections, Newstand, Books, Music, Video (but not videos you've added by USB cable, only ones you've bought or rented through amazon, digitally), Docs, Apps, Web.
Books I added by cable or e-mailing to the kindle don't show up under the books tab. They show up under the Docs tab. That's not terribly intuitive.
When watching Doctor Who on Netflix the volume control isn't easy to find. There's no reason to hide it and yet they have. That's a Netflix interface issue. Surely they'll fix it.
Overall. I'm very happy with my e-reader on steroids. I'm going to take it with tomorrow instead of my kindle keyboard and see how it goes. So far though I'm very happy with it.
I didn't talk about it requiring wi-fi to get anywhere as that's covered on the amazon site. I have it most places I go so that's not an issue for me. I'm curious to see how much of an issue the battery is.
More after I've had it for a while.
Thanks for making it this far.