With the seats, it's about style. Like any product, you pay more for it.
The SS114 is more of a clean design, the SS154 has a more traditional look about it.
They both have the slowclose feature.
The same with the Drake and the Dartmouth. Style again.
The Drake is a cleaner design, the Dartmouth more traditional looking.
They really look nice with some of the newer, older style homes with moldings.
If we were talking about faucets, you would notice that the same valve body and cartridge can be trimed out many different ways.
The Moen Kingsley tub shower Posi-Temp trim ranges in price between $131.00 to $320.90 based on finish.