Currently running Amazon Prime fire box on my TV. Works well. Good GUI and easy to use. They've definitely improved it over the past year as I've noticed a number of updates.
The shows I'm watching right now are primarily on Netflix. Seems like Netflix has the best selection out of all of them. I use that, then youtube, and then Pandora. Pandora is clutch for working around the house and I hit the "watch later" button on many youtube videos. Then watch them on the TV. Its quite nice sitting there on the couch watching a Warn 8274 teardown video vs. my phone. I do the same. When I'm on Amazon on my computer, I see what is new and then set it to my watchlist.
For amazon prime, what they offer is right there. Pandora, Netflix, and Youtube are all "apps" so you gotta go into the app then get to where you are going. Also HBO Go is on there but I don't use it.
Only issue is watch out for data caps. When the gf was home for 2 weeks with nothing to do, we hit the 300gb limit REAL quick. It seems like data caps happen in some places and not in others. Its weird. All I know is I have one and gotta watch out for it.
I'm planning on getting a chromecast soon. Mainly for when I travel for work so I can watch something I actually want to watch. For home, it would be nice to link to the computer to run ESPN3 or other