The customer support is amazing! They're always willing to help out with any problems you have as well as answer questions about how they can improve their product in ways not yet thought up by themselves.
I don't like having to use an API key for each user account when using diffbots through my website or mobile app - it would be nice if there was one place where all users could access this information instead of needing multiple keys per person/account. Make sure your content has unique URLs before uploading them via diffbots so you won't get duplicate entries added to your database. We were looking at other providers but we found most didn't offer what we needed (ease of integration).