And why would you create your own custom PDP? I fail to understand why people want to reinvent the wheels themselves. This is a trend I am increasingly seeing at companies.
A PDP's job is to evaluate policies. If our PDP is not doing that properly then there may be bugs (I have not seen any major bug reports and I have run our PDP in complex policies' scenarios at various interoperability events).
I am pretty confident that our PDP is robust and can do good for the features we have advertised.