Earlier quoted context omitted.
Amazon removing the Chromecast from their store was, if anything, verification at the Fire TV was not a product that could succeed on its own. I love my Chromecast and I buy new models directly from Google, because no matter what Amazon says I know the difference between Google's product, and Amazon's copycat version of it.
If they would give me an actual controller for the chromecast I might consider it I have no desire to control my TV with my phone. I may look into Roku as an alternative to FireTV now though,
The only annoyance is that they put ads on the homescreen, (but that can be blocked at the network level), and that different apps tend to have slightly different/inconsistent UXs, for example pressing "up" while watching Netflix will show you the timeline without pausing, but doing the same in HBO Now will take you back out to the show info page.
The dedicated remotes are nice, though sometimes oddly slow to "wake up". Some models even have headphone jacks on the remote, which can be really handy.
All the versions can be controlled through a really nice Android app, which lets you directly enter text rather than pecking around in a grid keyboard, and also lets you forward audio to your phone/headset instead of the speakers or remote.