I bought a new tv (sony x900e) that comes with android TV system. I haven't used it much and just connected it to the shield, now I want to just use the native android build into the TV. Do I lose much? Is the shield better hardware worth it? I mainly use kodi and Netflix.
The Shield is going to give you better performance with less possibility of stuttering and frame drops, and will also likely get updates and features more regularly. Plus, it does have some great features like Gamestream, Plex server, and Amazon Video (which might be coming to other ATV systems soon, but maybe not).
UI wise, I would wager that the Shield would be a bit snappier. Picture quality wise, I have no idea, but would hope that Sony does a decent job.
Raw processor power wise, you might not notice anything drastic. Running video apps shouldn't push the CPU hardly at all. In a perfect world, that is.
Like comparing a ferrari with a fiat, they both get you there, but the Ferrari gets you there faster and in style. How much does it matter for video playback? Depends on your media.
The TV won't have a great processor. It'll be "good enough" kinda like a Xiaomi Mi Box in terms of performance. The Shield TV is like a Ferrari with its Tegra X1 chip. Super snappy.
There's been a lot of posts lately about this TV. You should do a subreddit search for "Sony" to find a few. Like this one.
Hardware and performance on the SHIELD is much more powerful, so Android TV will perform quicker and more stable with the SHIELD.
Updates will be better on the SHIELD.
That's basically it.