Maybe 10 years ago there was a compelling argument for Sharepoint. It allowed users to collaborate on ideas and projects, acted as a central repository for information, and provided an alternative to group emails.
Nowadays, there is absolutely no reason to use Sharepoint unless your company is so desperately tied to Outlook and MS Project, that nothing gets done without them. Sharepoint is slow (in the ohmygawdslow region of slowness). It's bulky and you'll need a big server stuffed to the gills with RAM just to get it off the ground. Finally, Sharepoint is difficult to secure, especially if you plan on using it to collaborate with people outside the network (partners, clients, consultants, etc.). I've built and managed several Sharepoint installations in the past. Everyone hates them.
Instead of paying $10K+ for software everyone hates, we paid nothing for software everyone loves. Since we're a virtual environment, I built a simple Ubuntu Server installation on 1 processor, 1GB RAM, and 21GB disc storage. Then I just installed a MoinMoin wiki on top of it. We modified it to use Active Directory for authentication. Wiki is a technology that is familiar to all, and MoinMoin allows users to create things like graphs very easily.
Remember, ISO certification just means that certain activities are documented. So if, upon receiving an error notice from your Exchange server, your regular activity is to repeatedly bang your head against the nearest file cabinet, you just need to document it. Then you're ISO-certified. We are proud NOT to be ISO-certified. While certain activities follow a documented path, we prefer to treat most of our issues on a case-by-case basis, where employees are expected to collaborate and show good judgment. Following a script is for people we won't hire...