PEAR_Exception vs SPL exceptions

Hello All, Currently, it is unclear whether or not exceptions used by PEAR packages must extend PEAR_Exception. PEAR_Exception provides useful features like generating of pretty stack traces, registration of exception handlers and wrapping of PEAR_Error. On the other hand, having a single point of inheritance prevents extending generic SPL exception classes in PEAR packages. Of the existing feature in PEAR_Exception I think wrapping PEAR_Error is the most important. Handling exceptions and displaying stack traces could be performed by a separate class that would work with any type of exception (PEAR_Exception_Handler). Mike