First, there are ways in which Progress is actually superior to Oracle. Transparent Data Encryption is a better and more performant approach to encryption than anyone else and the new Multi-tenant features are a first in the industry.
Second, for a large number of applications the database is a commodity, i.e., almost anyone's database is good enough. Choosing among them is not a question of features or even often performance as it is a question of price, stability, cost of ownership (maintenance, etc.) and other non-functional requirements.
Third, the primary reason for choosing a Progress DB is that one prefers doing development in ABL. There is no ABL equivalent for Oracle and, while one can use an Oracle or SQL Server DB with ABL via DataServers, one is clearly better off with a Progress DB unless there is a compelling reason to do otherwise.
Time to get better informed. What was the purpose of this thread, anyway?