The biggest difference, and of EXTREME importance if you're installing it yourself, is that the Americast tub weighs about 110 lbs. vs. 350 lbs. for cast iron! I recently installed an Americast tub & I think it's great.
Summary: This impressive and accessible waterfall on the U.S/Canada border is the highest waterfall in Minnesota. Definitely worth a visit. The High Falls of the Pigeon River, also known as Pigeon Falls, is on the Minnesota/Ontario border, right off of Hwy 61. The Falls can be reached from Grand Portage State Park or Pigeon River Provincial park. On the Minnesota side it is a short walk to the falls on a pathed trail.
For more on the Savannah River, see the New Georgia Encyclopedia. The Savannah River orginates in Hart County at the confluence of the Tugaloo River and Seneca River (Seneca is in South Carolina). This confluence also forms Lake Hartwell. From Lake Hartwell the Savannah River flows southward for over 300 miles, forming the Georgia/South Carolina border. It empties into the Atlantic Ocean near the city of Savannah. Along with the Tugaloo River, the Broad River is also a tributary of the Savannah.