When it comes to an intranet, the interface is key: it has to be easy. It has to be clean. It HAS to be SIMPLE. Along with the simplicity, however, it HAS to be powerful enough to get employees what they need, when they need it.
SharePoint takes time to develop, and - whether you gowith the free version of SharePoint or Enterprise - development and design costs time and money.
The licensing alone - not including development costs - can be very expensive.