One main difference between Yasmin and Ocella is always going to be the cost. Ocella is known as a birth control pill that is considered to be generic. Yasmin is going to be priced more expensively because it is the branded version of the drug.
A lot of people are aware that generic versions of medications are always going to cost less than the branded versions. Another difference is the coverage of different insurance companies. Most insurance companies will provide coverage for Ocella but will not provide any coverage for Yasmin. This is something that you should consider, especially if you believe that one will be more effective for birth control as compared to others.