O2 sensor aren't rocket science, I've used Walker O2 sensor in my Integra and Corolla for more than 4 years and 60k miles each and they are both holding up fine. IMO unless you care about the very last 10% of their useful life O2 sensors are all pretty good nowadays, and when it reaches the last 10% of its life, just change it out instead of worrying about brand x is better than brand y.
BTW, the reason why most O2 at the bottom of the car (right in front of the CAT) last longer than the one under the hood right after the exhaust manifold is the HEAT. O2 last longer when it is further away from extreme heat in the exhaust gas, but having it warm up faster makes fuel economy better, the trade off today is to have its own heating element and further away from the heat, so it last longer and still have quick warm up.