Weird. That's the exact opposite of my experience. I've had a number of odd rejections that led me to reach out to a couple vendors (hey Amazon, I'm looking at you!) because there were small transactions attempted against closed cards. I've had a few hiccups for things like creating multiple cards to use with PayPal (there's an avenue for fraud there, apparently) but I've been able to get those resolved quickly every time. I have nothing but good things to say about their offering and it's nice to see they're opening a read API (I'm hesitant about write keys).

My only complaint right now is that some vendors (Google specifically) reject their card numbers because they're pre-paid and they've made a decision in the last year or so to stop accepting them. I know for a fact this is a new thing because I'm paying for a Fi account and a Google Music account using privacy numbers. When they finally expire, I'll stop giving Google money altogether.