Always talked to someone from USA and never had an issue with support.
I called yesterday after reading this post because I have a business Spark card, but don't have the 2% cash back. Ends up there you can be on the cash back plan or the miles plan (which is what I am on). Basically I get points, can spend them on travel, rewards, gift cards, etc. I almost always use my points for Amazon gift cards since you can get practically anything from there. Either way, they said if I wanted they would switch me to the 2% cashback right there on the phone. I opted to stay with the miles for now.
Limits were a pain to increase. I started off at $5,000, kept spending and paying off right away so I'd spend much more than my limit per month. They won't let you increase your limit until you've been using them for at least 6 months. Once I hit that point, I was still getting refused. Finally I had them put it through manually and got my limit raised to $50,000. They said I was getting refused after 6 months because at the time of trying to raise my limit, the card had unpaid funds on it (duh, that's because I'm always using it).
Best thing about the card is that they don't charge you for international transactions, so if you do a lot of business overseas, you don't have to pay all those stupid fees.