Microsoft rewrote the code so there was no more Sybase code, but it still followed Transact SQL standards. T-SQL is not as complete as PL/SQL and others. It is just that Microsoft is that 800 pound gorilla so people use their products.
My last job I did migration from Excel and MS-Access to SQL Server using VB 6.0 code and ADO recordsets to copy and sync up data. They key was to use a column named date modified that had a time stamp when it was last modified to figure out which record was the newest and back up the old record to a history table in case it needed to be reverted later on.