We've had a lot of folks switching to SQL Server from other platforms lately. They start looking at SQL Server because many of the other vendors are prohibitively expensive, and they also charge for things that come with SQL Server out of the box, like ETL, BI and Reporting.
But before they make the jump, we always recommend a proof-of-concept test. We want to make sure they include all factors in their Return On Investment (ROI) calculations, including reduced hardware costs, licensing and manpower. Keeping yourself honest here lets you make a real business case for one platform or solution over another.
The nice thing about that is we have a free set of tools that can do most or all of the migration proof of concept for you. They are called Migration Assistants, and you can find many major platforms here.