Currently using Django. Once I started playing around with it I haven't looked back. Although I am told cake php and a few other frameworks really do improve php.
they dont improve PHP. you still have to deal with PHP shortcomings even with a framework. But since you dont deal with low level stuffs your code might be more secure yeah.
PHP has too many unsecure apis accessible to beginners.
With Django for instance you have a view layer with auto escaping by default.You dont write unsecure SQL queries ,..., That makes a huge difference.