Is it reliable for the china transformer oil purification system?

Is it reliable for the china transformer oil purification system?

There're many transformer oil purifier suppliers in China, too many. How can I know the reliability and quality of them?

here below some suggestions:

1-Please don't only see the supplier's website. Because website can be very nice by money advertisement.

2-The searching in the top rank in the search engine is not reliable, because the supplier probably paid money advertisement to search engine.

3-Please see the supplier's company type, generally the state-owned company is more reliable than the private company. CTBU oil purifier is one state-owned company over 30years.