There are mainly two lines:
Legend and Standard Balladeer models have one large sound hole as on most acoustic guitars (Standard Balladeer, Legend, Custom Legend - produced in Korea).

Elites have several smaller sound holes (Standard Elite, Elite, Custom Elite - produced in Korea).

The first Ovation guitar model was a Balladeer (later known as Standard Balladeer)
There are mainly two lines:
Legend and Standard Balladeer models have one large sound hole as on most acoustic guitars (Standard Balladeer, Legend, Custom Legend - produced in Korea).
Elites have several smaller sound holes (Standard Elite, Elite, Custom Elite - produced in Korea).
The first Ovation guitar model was a Balladeer (later known as Standard Balladeer)
Ovation Guitar Company