Pros
The EIU gets great people through the door, largely through piggy-backing on the Economist brand. You get the opportunity to work with a truly friendly, intelligent and interesting bunch - special colleagues who you will remember. It's also fundamentally interesting to be working on politics and economics in different countries around the world.
Cons
The EIU is both the cash cow, and the mistreated younger sibling of the Economist Group. In real terms, staff have had a pay cut or pay freeze for every year as long as I can remember, to support a Group that doesn't believe the EIU can grow and just tries to strip out cost. This would be difficult but bearable if the EIU had decent management. Unfortunately it doesn't. All the leaders have come up internally and have no meaningful business experience; they simply don't know how to make the company perform. As such they protect their positions through political power plays - think of the worst cliches of academia. With increased pressure they simply lean downwards on their employees, demanding more for less and giving nothing back. The attitude to employee feedback is to cover things up rather than address the issues (look out for some of the obviously fake one line positive reviews on this site as an example of this approach). Sadly, the EIU has the most depressed and demotivated staff of anywhere I have worked - reflected in frustration, turnover, high rates of sickness etc. While it has many positives, you should be wary