1 - The ability to mix and match As a CIO, you can build your own optimal set of tools for your organization's unique needs—with tools you know will work the way you need them to.
2 - Freedom to apply leverage with a vendor, and ultimately, the freedom to walk away The freedom to adopt better, more advanced tools is critical in the rapidly evolving state of technology. There's a lot on the horizon and plenty of reason to stay open.
3 - Customer influence During rapid change, independent vendors have to listen to customers. Even veterans cannot ignore their customers. Customers tend to be able to influence product direction (of independent vendors) more easily.
He also considers that there's a downside to buying from independents. Even so, the advantage of an open system is clear. While supposedly "integrated" platforms might serve for today, open systems serve today's needs and also tomorrow's—as they leave a path open for rapid and unpredictable evolution.
I agree with him, when you are choosing BI tools, you should choice the better tools to attend your company, whatever the tools are the same vendor or not.