Hi Luvdisney,
The Fountains I were built in the late 80's vs the late 90's for the Cascades. They are 3 story buildings with no elevator access. Most of the Cascades are 5 stories high. Only the Lakes and Cascades have elevators.
The Fountains I will have the jacuzzi in the master BATHROOM, vs the master bedroom of the Cascades. They do not have a safe in the master bedroom and they are a bit larger than the Cascades in general square footage. I felt the size difference was most notable in the living room/dining room area.
So generally, while well-maintained, the Fountains I will be less modern-looking and feeling. The trees and vegetation around the area will be more lush and mature. Just an FYI, the newer Fountains II does have the jacuzzi in the master BEDROOM as with the Lakes and Cascades.
Some pics I've taken : Cascades :