Originally Posted by Left Coast

I agree, and seeing for myself caused me to conclude that his argument was very weak. He has his right to his opinion, and I have my right to assert my opinion that his opinion is based on very little research and no first hand experience. Since there is very little hard data to help us decide about many of the things that are discussed here, a variety of opinion and anecdote is about as good as we can get. I did see for myself, and I shared my results. I'll reiterate them: Google turns up few reviews on Monark plugs. Not all of them, and not even an overwhelming majority, are negative. Few of them are more recent than 2010, and that fact is worth considering in a rapidly changing world. Judging from the sample size and age of the reports, I found nothing that would influence my own decisions.

I recently read somewhere (and regretfully, I can't provide the link), that Monark did experience manufacturing problems in the 2008-2009 time frame, and they have since corrected their quality issues. I don't know if that is true.

While opinion is perhaps the best information available, much of the opinion shared here and elsewhere is regurgitation, and much of that is not quality information. Everyone should understand that and dig deeper.

Your own account of your experience doesn't indicate when it happened either. I'm not implying that your experience is worthless to me, but it carries nowhere near the weight of controlled test results. Unfortunately, there seem to be no controlled test result. BTW, I had the same experience once with a Bosch plug. Based on that, I wouldn't condemn all Bosch plugs. Would you?