Over the years I have noticed that typically there are more sedans on dirt and more coupes on asphalt.
The '34 coupe is more popular than the '37 coupe, we owned a '37 coupe and it was an awesome car but our biggest issue was the lack of head room.
The '37 or '34 sedans are just a different body, same chassis but the only thing I have heard about the '34 sedans is that they could be a pain to work on things in the rear because the body comes further back.
I think coupes and sedans have different characteristics but I don't believe one is better than the other. Basically, it comes down to what you like or dislike.