I have been learning that the OLED Tv's are supposed to be the smoothest with the highest refresh rate around. Apparently these are the best for sports?
You should do some reading on frame rate vs. refresh rate and image interpolation.
A high refresh rate doesn't mean anything by itself. The refresh rate is how fast the display redraws its screen. This may be 30 times per second, 60, 120, 5000...
The frame rate of the source material is another matter. Frame rate for all consumer video formats, currently maxes out at 60 frames/fields per second (60 Hz).
So, if the source material is coming in at 60Hz and your display refreshes at 480Hz, all things being equal, the display will re-draw the same frame 8 times before the next frame is fed to the display.
Now, you get to the fun part - image interpolation:
Some TV manufacturers decided, "Well, if I am CAPABLE of drawing the screen 8 times during 1 frame, why should I draw the same frame over and over again? Let's compare the current frame to the next frame, and find a way to "manufacture" 7 intervening frames to display before the next "real" frame arrives!"
These frames attempt to "tween" between frame 1 and 2 - in the guise of making things "smoother" but to many people, this effect looks artificial and distracting.
In addition, the processing used to create these frames isn't instantaneous (and in fact, needs some delay inherently, since it needs to compare the current frame to the next frame - so there is automatically a buffering process). The result is often lag between audio and video that is notoriously difficult to completely eliminate.
In the end, most of us find that disabling any sort of "smoothing" feature is ultimately the best solution.
Some find it "tolerable" for sports ("Hey, the yard lines are more straight and less jaggy!") but that becomes a matter of personal preference.
I would highly recommend that you take the time to audition a display with these features turned off (in addition to comparing the image when they are on), and avoid getting a display that has no ability to disable/defeat these features.