I wouldn’t use smartcast anyway. I have a fire stick 4K that I got cheap on flea bay. Actually the M series has great review on rting, but not smartcast is not loved, but heard recently it’s firmware update made it smoother. I’m not a fan of Roku either. Of course the Samsung has a great picture, but I bet the Vizio can match it when calibrated. LG, Sony, Vizio, TCL etc still provide great picture quality at budget depending on the series.
Edit look at the comparison:
Compare the Samsung TU7000 and Vizio M Series Quantum 2019 TVs
www.rtings.com