The ONLY way to tell is to go and watch the TV. Same program on both if you can. Flowing water I find is the best test.

Pick the one that looks best. Different specs and techs mean nothing if you don't like the picture. Your th eone watching it for the next 10 years.

Also how big is the room it's going into? You need the sapce on a large tv to view it properly. Generally (before people jump in ) you need to be seated at least 1 foot away per every 10" screen size plus a couple of extra feet.

So on the 46" you need to be 4.6 + 2 feet away. So about 6.5 feet
The 52" you need to be 7.2 feet away.

Also in general bigger tv's look worst overall. Same number of pixels over a larger area along with light source in the tv.