The only thing I do not like about Samsung is their tendency to have rather high prices, but I know they are a rather great company (I own an S3 and other Samsung products). I like the Vizio size, but it may be a bit too big. Plus unlike the Samsumg, it only has one HDMI, so I like the Samsung so far and will look for reviews later.
I'd buy Samsung, it has always been a great company. The TV is 200$ atm it is 300$ normaly, but remember its LED. LED tends to cost more than other HDTVs.