I usually turn of any motion processing/smoothing to let the TV show what is coming in on the video feed.
About "exact kind" do you mean exact model? There are plenty of articles and discussions that UHD 4K is well, not that big a step up. The charts at http://carltonbale.com/1080p-does-matter/ show why you might not see a big difference.
When many sales folk demo you notice they take the client to just a foot or two from the screen to show off the extra pixels. But as the article and chart shows, in normal use it's rarely seen.
Bought a Sony Bravia 65X900E 4K TV for $1500 a month ago from a local TV place here in Marin County, CA. I was hoping to get better picture quality than my 5 year old 60" Samsung. The picture quality of sports, especially Warriors basketball, is worse than before. Though I watched Blade Runner 2040 thru Comcast On Demand and the picture was probably a bit better than on my old TV. Overall, this new TV is disappointing.
Part of the problem is that Comcast does not yet offer 4K format. But since the TV has more pixels than before, sometimes the picture quality is very good, like during commercials. But the new 4KTV cannot keep up with the action during a basketball game so you get more blurriness than before.
I researched 4KTVs quite a bit before buying (including CNET) and did not see much on this.
Another part of the problem is that sites like CNET offer reviews on very specific TV types; it can be hard to get a review for the exact kind of TV you want to buy. This is probably purposeful. The TV companies come out with so many slightly different TV types to make it difficult to compare oranges to oranges.
After many tries I finally got a new 4K cable box from Comcast. It has not helped the picture quality.