I bought Chromecast for one of my bedroom TVs; my wife loved it so much that I moved it downstairs; we have been using it a lot more than my HTPC. I only use the HTPC to watch movies and run 'background tasks'

The simplicity of the casting ecosystem (everything from common phone apps) makes the Google/Android option a lot easier for my wife and guests to use. I still have some work to do to see how Kodi/Plex can be leveraged effectively with full features (4k with HD sound, subtitles, etc).
I'm looking at the Shield because:
1) It supports 4k (Netflix,YouTube not supported with Windows HTPC)
2) Casting options from phone (YouTube Netflix Twich Pandora)
3) It's only $199 for the base model which is a ton cheaper than even the cheapest 4K HTPC solution
I'm still upset that Windows Media Center got dropped, I loved that product and spent a lot of time on it

Erwin