| Pros |
| 1. No interoperability overhead to access the legacy part of application business logic from the .NET part of application business logic and vice versa. |
| 2. Less risky, lower cost and time if it is difficult to slice business logic for local or vertical migration. |
| 3. Good opportunity to redesign the application business layer in order to take advantage of .NET. |
| 4. Migrating COM objects to .NET classes improves scalability. |
| Cons |
| 1. Additional interoperability overhead to access the business logic from the presentation layer of a legacy part of an application (if the presentation layer is not migrated yet). |
| 2. Additional conversion to a recordset or other COM data formats for a nonoptimized presentation layer. |
| 3. Generally higher risk, time and cost compared to the interoperability option. |
| 4. .NET Framework has to be deployed on all servers, where business logic assemblies are deployed. |