Nippondenzo A/C Compressors

Just thought I would ask the group if their experience with Nippondenzo compressors has been as bad as mine. I have replaced compressor two times within the past 2 years. The first two proceeded to lock up on me , and the third one had speed sensor problems. Positive side if there is one is that the first two were covered under warranty and I did not lose any money per say. The third compressor was out of warranty so I had to cover the repair cost. Are these compressors a piece of junk or what gives? All the compressors were new and installed by a local independent MB shop. The mechanic is a friend of mine and he has done countless A/C compressor change-outs. I even helped him replace the last one. Comments appreciated. Johnny

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