I believe we're in a transition period, with another year or two for shake out. I can only speak from experience with a non-smart TV.
Some thoughts:that may be the best combination for alternate uses, an N200 Sony and a Roku HD.
First, the connections. This is important to me, as It allows streaming from different sources.
The Sony has the best combination.
USB from any source
RCA Coax only
I like the Sony, because I can use it to stream anything from my 3Terrabyte drive, anywhere... direct... no computer needed. Works great at camp where there is no internet access. Also, the Sony has UTube built in, and has a very intuitive search option... one or two words in title gets the program.
The Roku (HD) doesn't have UTube built in, though you can add it, using the developer mode. Roku has added many, many specialty channels, though not much that interests me. Usually filled with ads, or short clips that are a nuisance to get to.
A little off topic, but some stuff that's available to supplement streaming video.
A search program for YouTube movies, of which there are many hundreds available. (takes a while to load, but worth the wait.)
A search tool for Netflix that is interactive for types of videos, by genre, years, and many subject categories, along with reviews from Rotten Tomatoes, NYT etc.
By the way... Using the USB input on the Sony media player, allows you to use a wireless keyboard and to surf the internet on the TV or monitor.
Since I don't have a Smart TV, I don't know how much of this is available, but I DO like the portabilty of the media player, which allows me to use any kind of input on any kind of output device... anywhere.