I bought an Autometer Cobalt Wideband O2 gauge (#6178) from an eBay seller ihavethebestpriceperformance69
(The cheapest price I have seen anywhere).
The whole unit is pretty awesome. It uses the typical 6-wire Bosch wideband sensor, all the electronics (Sensor heater, calibrator, etc.) are contained inside the gauge housing, so all you have to pass up into the car is a tiny 10 wire harness. I was able to slide it up through the hole by the ECU without even having to remove the heatshield above the exhaust.
The gauge has a 0-4V analog output to use for datalogging, and it's fully adjustable. You can set what value to use for 0V and what value to use for 4V, and the output is linear between the two.
The gauge also has a momentary switch option (to use for WOT) to use the peak/hold feature. You can set it up to trigger off a WOT switch, and once you go off WOT you can display the peak AFR you hit during that run. It also has a warning function that is in effect only when the switch is triggered, you select the AFR to start the warning at, and if you hit that value or higher, all the LEDs on the unit start to flash.
The unit is also adjustable for fuel type, you can switch between AFR and lambda mode, and choose what AFR is shown for lambda values (ie 14.7 for gas, or 9.0 for ethanol).
Installation was ridiculously easy, one end of the harness snaps onto the Bosch sensor harness, the other end snaps into the gauge, then you connect the red wire to a +12V on ignition source, black wire to ground (optional: brown wire to WOT switch), and that's it. It took me longer to unbolt the plug in my downpipe then it did to install the gauge itself.
Total cost for the unit was $290 shipped, so it's more expensive then the Innovate or AEM, but still a good deal.