That's what I did, the Ultra for $99. I like it has more free content and cross channel searches with price listings. Surprised how often someone has a movie for free. The interface is better too. I even think the Amazon movie app works better on it than their own devices, fwiw.
I bought the firetv because it was droid based and you could load apps on (though kind of a pia). I had an app that made it kind of like Roku: the apps I want laid out how I want on one screen, and it would wake to that screen. Amazon went in to MY streamer and deleted the app, and others. It was cutting into their advertisement and their money stream. I am not an amazon fan anymore.
Sometimes when I'm looking for a product I'll go there. Fortunately they haven't hid the "sold by"..... yet! However, I won't buy from them anymore because they won't let me check out as a guest. When you log on they spam you with trying to get you to become a prime member or get a cc. I accidently made a wrong click once, literally EIGHT screens to undo it. That's not an exaggeration! Eight! As an aside, Walmart is following the Amazon model, Marketplace Sellers, allowing other vendors to list on their site. But you're not being spammed and you can check out as a guest. Vendors have to meet certain standards to sell there too.
The truth be told, it's hard not to find free shipping anymore. Pretty much 100% of the time if you google the "sold by" company and go directly to that site they offer free shipping and the same price too. Go figure....
Sorry for the rant