I'm looking to spend less than $500 or $400 I saw the vizio smart TV 39inch E3901-A1 which says 1080p and 120hz but I read reviews and it says it mostly works like a 60hz according to cnet and also I saw the Samsung 40 inch smart TV UN40EH5300 it says it has 1080p but it doesn't say 120hz but its 120 motion capture I can't decide on which one I'm also getting the ps4 so I don't know if to choose between those 2 or other options because the ps4 comes with netflix hulu etc like the smart TV. I need help from some TV experts don't know what I should get help please.

Why are you so hung up on the 120 Hz refresh rate.
The real important factors here are size and Full HD (1080)
Which design do you prefer, yes it's that simple really.
After all you will have to live with it.

Well I don't really know what to pick I never had a vizio or Samsung it would be my first TV I want something not to expensive and get something worth the money that's why I asked to get people's oppinions.

Korea is well known to be the current leader in TV design and quality. That means Samsung and LG. I've had both. I sold my smaller Samsung to someone who had a perfectly good Vizio because side by side, the Samsung had a better picture. I now have a 55" LG and love it, and the company has good support too, and they honor their warranties. (But I paid 1400 for it - you get what you pay for, and I did a lot of online comparisons.)
I think refresh does matter if you are watching very fast motion. Lower hertz shows as a faint blur around the edges of the action. But you have to really be looking for it. Maybe if you are a gamer it matters.

There is no question that Samsung has the best picture. I recently had to replace my old TV (a week ago. And I looked at a Vizio 50" for $450. But the Samsung picture was so visibly better. I decided to go for that even though it was $200 more. I also got a 5300 series which I believe is 60Hz. But I couldn't tell the difference between that an the 120Hz. I think the only real difference might be if you use it as a gaming monitor.