French Quarter is a smaller, more compact layout. Nothing is a very far walk to the main building with the front desk, food court, bar and store. It has a single pool but there is a pool bar. The French Quarter does not have a table service restaurant.
Riverside is much larger and it can be a long walk to the main building with the feature pool, front desk, food court, bar, store and table service restaurant. There are also several smaller pools scattered around the resort.
All the buses at French Quarter pickup and drop off at a single location. All the buses at Riverside make stops at multiple points as they circle the much larger more spread out resort. The two resorts share buses only during the non-busy hours. When they do share, the French Quarter is picked up or dropped off first then the bus makes the rounds of the multiple stops at Riverside.
The boat to Disney Springs stops at both resorts.
In my person opinion, the French Quarter is the more adult orientated and has better over all theming.