[Vaismania]

I'd argue on the fact that having two business oriented co-founders can sometimes hurt you more than having a lone co-founder.

[Geekette]

I don't see how a 2-bizhead team can hurt, unless they're focused on an market outside their areas of expertise/work experience.

A lot also depends on the type of product. E.g. for a consumer oriented startup with a tech-enabled (not tech-centric) product, the immediate big challenge (assuming business model has been established) is often sales & other "businessy" challenges.