Agree with angersock. It's really hard to know what you're looking at with such a vague description. It's hard to give any kind of good answer with solid recommendations without more information for a company of that size.
With 1K employees, no one thing is going to provide best fit for everyone. Work out what the internet is for, and realise that you might end up using multiple systems for different uses, and find ways to use them together. That's a good thing, because it means you don't have a single monolithic companywide dependency.
