In Clementi and seeking pizza alternatives to Pizza Hut? Definitely give Pizzaroni a try. They serve thin crust pizza by the slice or whole pizza take away (they do have a small spot for dine in, but can't fit much more than three people).
What's great about this place is you pay a flat rate for each pizza size, so there is no additional charge for toppings. You can add as many toppings as you would like. They also always seem to have deals on the second pizza.
Basically this is a no frills pizza place that bakes a decent pie.