More than 10 000 customers currently. They even launch a give away to celebrate that:
https://bitcointalk.org/index.php?topic=5124774.msg50321667#msg50321667

I've tested it only with faucets but I've managed to boost them x100 to test withdrawals. It was on my wallet in the blink of an eye.

And their withdrawal fees. I've didn't see that low ever.