SSI v PHP

[Nevermore]

I am relatively competent with PHP - i.e. I can make it do what I want quite quickly and easily - but I just acquired a server that supports SSI. Are there any advantages of SSI over PHP4? I want to know whether it would be worth knowing both.

[pyro]

I don't know much about SSI, so I could be way off here, but my impression if it is that SSI is no where near as powerful as PHP. SSI is not even close to being the caliber of PHP.