Better things to do in Ottawa
For some reason everyone likes going to the Rideau Falls. It really is boring, and after you've seen the Niagra Falls this falls (pun intended!) very short of beautiful.
I did not do the cruise, however, so cannot comment on that. Everytime I go with out of towners, we just walk up to the top and view it from above.
Summary of people's reactions:
Kids = bored, teens = waste of their time, adults = oh nice. (I wonder why this is a tourist attraction?)