Forrester Research analyst Noel Yuhanna posted a blog entry titled "Database Migrations are Finally Becoming Simpler". Based on customer feedback he got, one can see 90% or more compatibility and hence the migration effort for moving from Oracle to DB2 requires only days or weeks instead of months or years. Noel Yuhanna says "This is huge".
Database customer want to save millions of dollars, but earlier a migration was costly and painful and required a larger investment of their own. With the DB2 compatibility layer the migration becomes simpler.