how reliable is the COM extension from PHP 5?

Question

I am playing around with the PHP5 COM extension http://de3.php.net/manual/en/book.com.php by creating my own dll in C# and using types from it in PHP.

Apart from the minor annoyance that my dll apparently has to be installed in the GAC my toy app did work.

I am wondering if anyone used the COM extension in a realworld project.

What I noticed so far: It seems like debugging could be really tough, most of the time a simple "com_exception" is thrown in PHP if something goes wrong and the stacktrace is not really helpful. And maybe performance is an issue, the loading and especially the unloading (?) of the dll seems to be rather slow.

Any experiences to share?