As above, 120hz isn't necessary due to the 60fps limit, but most sets are 120hz anyways these days.
Besides input lag, the other feature I would look at is the backlighting array. Most are edge lit, while some of the nicer sets have full array backlighting. This will give you less light bleed and usually much better contrast and deep blacks.
I'm not a huge Vizio fan, I bought them a lot years ago when it was all I could afford. They all lasted but developed niggling issues. But, there are some Vizios with full array backlighting that received exceptional reviews... The M and P series I think. Might be worth it considering the excellent prices on Vizio.
Otherwise, stick to Samsung, Sony, and LG. I got my Samsung a week before Black Friday online and that turned out to be the best deal available last year. It was cheaper a week out that even on Black Friday itself. So look early. I got mine from Walmart.com. it was cheaper than Amazon for the model I bought.