[HO455]

I have a Innovate dual O2 guage installed on my Burban. It is a 350 SBC with Qjet and headers. A pretty generic engine. After tuning the carburetor and having it on the truck for a couple of years I don't believe that there is much advantage to having the dual set up. You can dial in the idle circuits so the mixture screws are the same and the O2 readings are generally within .05 to .3 of each other. (i.e. one side is 14.57 and the other is 14.74). If that difference matters to you then go with the dual sensor model and you can get them closer.

But is it worth the extra cost? To me not on a driver. I would rather spend the money to have some data logging capabilities to help dial the carburetor when driving. Like how rich is the power circuit and what RPM is it coming in at? Is my accelerator pump shot too lean or too rich.
One problem with the aftermarket O2 guage systems is the sensor life is poor. I personally believe it is because compared to a OEM factory system the power supplied to the O2 sensor is poorly regulated resulting in power spikes and lows that damage the sensor. The OE's are responsible for the vehicle's emissions for 100k miles so they have engineered a proper power supply to the sensor. The aftermarket is really only worried about their 30 to 90 day warranty. I have no real proof of my theory at this time but as both my sensors currently are dead I will install some sort of power protection before replacing them. And that should prove me right or wrong.
Do some research there are lots of tales of woe about dead sensors and at 80 bucks a pop it isn't fun. Not to mention all the Chinese knock off sensors in Bosch packaging.
That being said I have zero experience with the Edelbrock system.

Bigdav160 has an excellent idea if you go with one sensor.