I've got a "smart TV" and can tell you that the UI they provide is crappy, slooooooooow, glitchy, and hard to navigate, even with the tinsy (yet clever) remote they provided (yes, Vizio, I'm talking to you). However, if you want to get an idea of how this device will operate, try pairing your phone to the YouTube app. Amazing? Yep. So much more useable than a silly remote. Plus, you'll likely be able to watch whatever service makes an app. Boom!
I'm sure you aren't their target market. Personally I went for a bare bones TV because I have so many peripheral devices it made sense to keep using those.
Also - Can you stream games and other random apps to your TV? I would assume this would let you in the feature with supported apps.
Sounds like it - Netflix is what, $10/mo? Pulling that off the top of my head. After tax it was ~$42 with basic shipping - so more than half off it sounds like :-)
For me, it is the ability to control the TV from my cellphone, tab or mac without dealing with the terrible keyboards on the smart TV remotes (PS3 input is only slightly better).