There are plenty of horror stories of Paypal holding funds. They've been doing it for far longer than most these other companies, since they've been around longer than most of them.
Much of them are older, because honestly Paypal had quite a few years of being the vendor of choice before a lot of alternatives came around. I'm not sure if that means Paypal had enough competition that they had to deal with their behavior or they're just used less so you hear about the problems less, but for anyone that's been around for a while, hearing about Paypal screwing someone over is not going to sound like something extraordinary.