Pros
I worked with Betfair for more than five years and I was really happy with the organisation. Its a classic example of a successful dot.com story. Most of the engineers and managers, I came across were really smart and highly skilled in their jobs, so the opportunities I had to learn from them were available in plenty. Anyone who loves technology would enjoy working in Betfair.
Cons
Like any other organisation, things started changing when the firm was being run like an investment bank. Going public and changes in the senior management severely impacted the inherent culture of the organisation. All the experienced personnel who built the company left the company. Redundancies over the years have also not helped preserving the talent and the tacit knowledge people had about the organisation.