Personally, I like PHTML more, because file-managing is easier, the number of predefined tags is greater, and the possibility to specify a complicated tag is better.
What also is a great plus, is the ability to define tags yourself. As a added bonus, PHTML is cheaper.

To be improved:

supply with HTML documentation
add HTML-validation
PHTML: add META-tags
Plus:

PHTML: Many predefined tags
PHTML: Ability to define your favorite tags yourself.