There are so many wideband controllers in the market. Everybody is claiming his own is the best.
I have some suggestions to compare one wideband to the other, ask some questions and see what answers you can get:
1) Is this wideband controller able to be used as the feedback device?
If yes, this is a good one. As a metering device, accuracy and responding speed are the 2 most important characteristics of a wideband controller. Only by having a fairly good accuracy and fast responding speed can a WBO2 be used as a feedback device. Meaning it feeds back the AFR or lambda to the ECU (engine control unit) so that ECU can run a continuous close-loop fuel controls.
A lot of wideband controllers can only be used as an open loop device, meaning, reading AFR and display it on a gauge. If used as a feedback device, it could be either too noisy or too slow to be really useful. These WBO2 can not be recognized as good ones.
2) Does this WBO2 requires "free air calibrations"?
If yes, this is not a good WBO2. Because: first, WBO2 sensors are most accurate around lambda of 1.0, but least accurate at free air. Using free air to calibrate a WBO2 is to use the least accurate range to calibrate the most accurate range. You are losing accuracy by using "free air calibrations".
Second, free air is different from one place to another. WBO2 is a device to measure the O2 concentration basically. Obviously O2 concentration of free air is different between your garage air to the air in the open area. The free air in a big city is going to be different from the one in the rural area. And it is different from coast areas to mountain areas.
3) does this WBO2 have the self-diagnositics capability? meaning can it detect a bad LSU sensor? or broken circuits?
If no, this is not a good WBO2. LSU sensors could be damaged if not used appropriately esp. during tuning process with some un-prepared engine operation conditions. If the sensor is damaged or derated, but the wideband controller can not detect it, it is obviously mis-leading and useless.