My car has been bogging down when cold during acceleration. It goes away after it warms up a minute or two. From what I have read here I believe it is a bad front O2 sensor.

So I plan to replace it but have a question, has anyone used the cheap sensors seen on various parts sites. They run around $30 dollars as opposed to the OEMs or brand names that run around $130. What is you experience, ratings on the sites are good but I would like to hear from people here.