It depends weither your car is an Se or Msport.
For an SE the prokit is perfect as the SE will drop more on springs as the suspension is softer, It will give a nice drop and more comfort than standard springs.

For an Msport I would go for sportline as the prokit will not drop an msport enough in my opinion.
The sportline is not as comfortable as the prokit but will give a nicer drop and retain the same comfort as the standard Mport springs, But if you go for the prokit the ride will be MORE comfortable than the standard springs.

Either way the ride comfort will not be any worse, thats what I have found from running both kits on different cars.

It just depends what your priority is I suppose.