I'm happy using an MVC framework like code igniter. I find that in the 'views' I tend to stick to php code that relates only to how values are displayed. I have a library of formatting functions i can use in the views to that effect. One of the premises of code igniter is to avoid a templating language because of the way it can restrict you and the slow down incurred.
I find that is better for designers to learn some PHP, so that they can achieve what they need to do eg. alternating class names. It will also make them more useful in the long term and it's not a huge leap from one syntax to the other.
