Here there is a short list of motivations that should convince you to at least try PyHP:
Python is a rock solid, fast and well supported language.
It has been around from almost ten years now and it has a great and strong community.
Python APIs do not change with every major release.
If you have been using PHP module for a while, you certainly know that PHP module APIs are very volatile: they change breaking backward compatibility very often. This does not happens with Python, which has a very strong backward compatibility: usually very old scripts just run on new version of Python without any changes.
Python has a very coherent APIs set.
Python APIs are very coherent and easy to learn. As opposite to the PHP module language, where you can have completely different API approach for the same object, depending on the function you are looking at: just to make some examples, take a look at the PHP Array object: you can see that many functions start with array_ and many don't, furthermore, these are all functions while in Python arrays are real Objects.
Python is a real OOP language.
Python has always been a real OOP language, while PHP module has added (and changed!) OOP over years.
Python has a rich library set
Often, Python is referred as the language with batteries included, because, by default, it has a very rich library set, designed to be coherent with the Python language from the beginning.
PHP module comes with a lot of commands, but they are not coherent with the language itself (expecially considering that the language itself is not coherent :-) ).