Here're some relatively independent comparisons for you to start with:
As many have mentioned before, validate your requirements BEFORE looking at BI vendors. Try to break them into
architectural requirements:
- performance,
- # total users and concurrency
- security,
- amount of data (raw data, and how many dimensions)
- administration
- monitoring for reliability
- deployment issues (web plugins, client installs, migration from dev to test to production etc)
- total cost of ownership (software, hardware, developers, maintenance team, training)
User requirements:
- types of analysis required (simple sums or running averages)
- types of reports required (formating etc),
- query types (user selections, canned or full ad-hoc)
- usability
- other misc : writeback, email distribution, links to operational systems
The BI space is consolidating, here are some major players in no particular order:
cognos, business objects, microstrategy, hyperion.