While YouMap doesn't work with Netflix, that's a non-issue for Fire TV users; Netflix already supports casting to Amazon's media streamer out of the box. Just look for "Fire TV" in the Cast menu from Netflix's iOS and Android apps.
A couple other quirks worth mentioning: YouMap doesn't support controlling volume with your phone or tablet's hardware buttons, as some apps do with Chromecast. Apps that have on-screen volume controls seem to work fine. Also, if the Fire TV is in sleep mode, you may have to initiate casting twice, as the first attempt merely wakes the device without actually making the connection.
A useful app, with risks
I've written before that Chromecast is a love-it-or-hate it device. For couch potatoes who always keep a phone or tablet handy, using a touch screen to browse and send content to the television can feel borderline magical. Adding those capabilities to the Fire TV could be well-worth the $8 asking price.
My only concern with YouMap is that Google will at some point shut it down. Even though Google doesn't have control of the Amazon Appstore, it can still stop unauthorized cast receivers from working, and it has done so in the past. You could very well spend $8 now and be left with a useless app a few months down the road.
What are your other options? If you haven't already bought a Fire TV, you could pick up an Android TV device such as Google's Nexus Player, Razer's Forge TV, or Nvidia's Shield Android TV. All of them include full Chromecast functionality, along with a proper remote and TV apps. Just be aware that none of these devices offer an Amazon app, making them non-starters for Amazon Prime subscribers.
The other option is to wait things out. Amazon recently launched Fling as an answer to Google Cast, and while its app support is sorely lacking right now, that could soon change soon; it's supposed to be quite easy for app makers to support Fling if they already work with Chromecast.
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