We stayed on the Canadian side for two reasons: most of what we wanted to do was on the Canadian side and just about every tourist site you'd want to see has parking lots you must pay to park in. It can get expensive very quickly if you don't plan your trip for this. Also, it makes sense to get an Adventure Pass for $45/each- you get discounted admission to Nature's Fury 4D movie, Journey Behind the Falls, Maid of the Mist, and White Water Walk, as well as coupons for the Butterfly Conservatory, the Whirlpool Aerocar, and more. It also provides FREE trips on the People Mover buses bypassing the need to constantly find and pay for parking. You can ride the buses without the passes, but for a fee. We used the website http://www.niagaraparks.com/attractions/
to plan our trip.