Short answer: everything, except for the Major Integration Module. This module includes integration with Dropbox, memoQ, SDL etc. But these are not yet available anyway, so don't worry about that just yet.
You get: unlimited users, unlimited projects, workflows etc, fully functional software that you can set up to your liking and start using.
Except for the Major Integration Module, You also get ALL our future updates, bug fixing, all the times, no questions asked. You even have a saying in what to develop next.
Oh and, you also get the prices grandfathered, which means, they never change.
You also get 1 hour of support for setting your server up. Usually this is enough.
And finally, 1 hour of direct free support per month (like, skype talks kind of support - the e-mail etc support is, and always will be, free of charge)