While currently this website doesn't advertise, when I encounter products that are either well made or good value (and just occasionally both!) I'll write about them.
The first thing to say about this device however is its worst aspect, namely its cost, it ain't cheap, that said its still worth considering.
My main reason for getting this box was to replace the hopeless "smart" features implemented in the somewhat limited fireTV OS on my TV.
The hardware spec of the Shield puts my budget 50" TV to shame, in the time I've been using it I've never noticed any lag in the UI its always responsive, and a genuine pleasure to use.
I've previously used cheap TV boxes before and despite not being officially certified for Google Play (often some apps aren't available) they have just about done the job. Its no surprise that the Shield is a certified device, and there is a wide range of apps available for it.
In contrast to the implementations of fireTV that I've encountered, where you have a very limited set of customisations available, probably to ensure they can further commoditise their product (you), the shield has a decent set of customisations, even down to which preview streams are shown for your apps. There isn't a large number of "baked in" apps (I'm looking at you Samsung) and they can be disabled, with the remaining uninstallable. Its refreshing to see a major vendor implementing Android without forcing a tonne of junk on you.
While Nvidia probably meant for this device to be primarily a mobile gaming platform on a TV, a dedicated gamer is unlikely to be satisfied with the games available from the Play store.
Clearly where this device really shines is as an Android TV device, done right, as it should be.