As with every business, especially a massive one like paypal, there are going to be people who aren't satisfied and of course some mistakes will be made with some customers.
I personally haven't had any problems with them and find their services quite convenient at times. There are some niggly issues with the interface, much too basic for some of my needs, and the features that are available would seem very hard to implement for beginners as they are hidden away and not really straight forward or well explained. But for the simple stuff, reliability and security, it gets top marks from me.