Seems most find the top link more valuable...
For me, I'm still up in the air about it. Now my setup is different than most, as I have two tilt cylinders, and I have an extra float section on my control valve which I REALLY like. Also, except for the float section of the control valve, the other three sections have built in pilot-operated check valves, so drift down is not an issue.
I LOVE having the option of float on a tilt cylinder. Here in Western Pa, at least where I am, everything seems to come in compound curves. When plowing snow with the back blade, or using the landscape rake to drag crushed stone on a surface that goes from high on one sided to high on the other, the float lets the rake/blade follow the ground surface much better than the 3PH alone does.
Still, I guess IF I could only have one of them, I probably would go with the top link too. In the beginning I spent too many hours leaning back and manually adjusting my top link when using the box blade. And the top link is key to setting the position of the cutting edge of the rear blade or the height of the tynes on my rake (both when using gage wheels).