You should refer BI tool evaluation kit and overall tool landscape to get some detailed back-ground. In-brief, there are two kinds of tools groups

• Core BI platform tools- Data Warehouse server, OLAP server, ETL tools, Data-federation tools, metadata management tools, data integration tools. These tools have a long list of capabilities, which form the foundation and core of your BI platform.
• BI end-user tools- These are the tools, which sit over the core BI platform, and used to generate information out of the data stored and administered in the core platform. examples of these kinds of tools are- Enterprise Reporting, Analytics tools, performance manager, data mining tools etc...

Doing first things first, an organization needs to decide the vendors for their core BI before anything else. We recommend that get all these core components from a...

Single vendor

This is similar to getting all the plumbing for your building to be done by a single contractor, while you may buy your bathroom fittings from different vendors. The core platform components need to be well integrated and their level of integration drives the performance. In case of multiple vendors for the core BI platform, you have a the following disadvantages-

• No end-to-end responsibility
• Investigation of issues, will involve multiple parties
• Any change that you will do in your BI model or dimensional model will need to be worked upon by multiple vendors.

In-brief, a single vendor will take away all these nightmarish scenarios. This is similar to you having a single ERP vendor instead of having different components from different vendors.

Therefore, if a vendor is selling you an ELT tool or a 'data-integrator' on a stand-alone basis, one should explore his overall end-to-end BI capability. As a side note, some of these stand-alone products are very good, but they do not become strategic, if not part of an integrated offering.

Financial Robust and Large Vendor

BI space is going through a lot of turmoil for last many years. This is manifested in the spate of acquisitions. At any point of time, half of the BI industry is acquiring the other half. Therefore, it is must that you go for the top line BI vendors, who are financial strong, have depth in their organization and also large number of implementation. This will ensure that vendor will keep on investing the future road-map and also the existence of its products will not be significantly impacted by any acquisitions.