I have used Oracle and I've used IBM Db2. I switched due to the job I had. Their new tool was SQL Server.

I work with Oracle, too. Data Warehouse is stable and expandable. The choice of solution depends on our customer’s requirements.

I've also used DB2. 

We are using Pentaho Data Warehouse in addition to this solution. We select which one is implemented depending on the customer's request and what they want to do.

Prior to using this solution, we used Oracle. We switched because my daily requirements are on Microsoft SQL. 

Prior to Microsoft Parallel Data Warehouse, we used a standard relational SQL database. We switched because of the performance and because the data and KPI changed. It would be difficult to use a relational database. We switched to a data warehouse solution because it was acceptable.

I have used Netezza as an MPP solution for around eight years, and from my personal experience, I believe Netezza has an edge over PDW due to user friendliness.

We switched from the standard SQL server 2014. We use PDW to improve overall ETL and report performance.

We didn't previously use a different solution. Our customers chose this solution.