I recently worked on a project that required payment profile management/purchasing and refund functionality for an ecommerce site.
CyberSource was the gateway I was to work with. I wasn't quite sure what to expect going into it, but I have ended up with a very high respect for the company and their support staff.
The documentation is thorough, but somewhat fragmented. I got most of the information I needed from the docs, but I was left scratching my head a few times when I could not find the details I needed.
Calling tech support is always low on my troubleshooting list, but after spinning my wheels for a while, I decided to see if they could provide any clues. I was prepared to wait on hold a while, then maybe plead to speak with another tier of support, or possibly be directed to developer forums where I would have to ask my questions.
What I wasn't prepared for is this: My call was answered right away. The first rep I spoke with answered an API question very fluently, seeming not to have even opened a reference. He then emailed me an API document he thought was relevant to my issue. After hanging up, I confirmed that this document was exactly the reference I needed.
Wow, did I just luck out or what?
I forget whether it was later that day or the next day, but I only spun my wheels for a little while this time before I picked up the phone to see if I could get a quick question answered. There was no wait and I was really hoping to get the same rep. I was a little disappointed when I didn't recognize the name. Let's give it a shot... I remember the name of the last rep in case this doesn't work...
The technical API question was answered, again, with no hesitation by someone entirely different. These guys know their stuff and are happy to help you. The third and last time I called them, few days later, I was met with the same caliber of support.
I have never experienced such competent developer level support in my career.
Oh, did I mention I wasn't even a CyberSource customer or inquiring under my client's account? I signed up online for a test account late at night and was able to start working immediately. Every time I called in, I just gave them my test account name and they treated me like a long time customer.
Customer service aside, I was able to do everything I needed for the project with their API.
These guys have earned a high recommendation to current & future clients of mine.