I'm actually torn about what should be a proper rating on this one. The CN Tower itself is something you should definitely see. It's a tourist-must. The views are astounding from the top.
But the utter crap you go through to get up there is ridiculous. They charge you an arm and a leg to get in. You stand in a long line. You go through a full body machine as if you're in an airport. You then wait in another line for the elevator.
At the end, you pop out at a gift shop, which may have been the most expensive gift shop I encountered during my time in Canada... and, trust me, I visited many gift shops.
But hey, I guess all that is to be expected at an attraction that people travel across continents to visit.
So in all: I give four stars. Mostly for the views of Lake Ontario and Canada's largest city. That's what makes it worth the hassle, after all.