We have used Diffbot for several years, their API for text extraction is extremely powerful and accurate. It has become an important part of our data processing pipeline. Their API(s) allow us to convert unstructured HTML data into information we can ingest and store.
Their support is also very responsive and has always provide us with value answers and feedback when needed.
We're a happy customer for about 6 years now, and we tend to forget Diffbot is there, since their data flows seaminglessly. Our work depends a lot on data processing, and we don't want to worry about how data sources provide their data, or when change their process along the way. With Diffbot we can really focus on processing.