We used Github Enterprise at my last workplace, paying $5k/yr.
We could have easily paid $300/yr ($25/mo) instead if we just used the normal Github site and had a better experience (they were constantly shifting things around to avoid the 20 user cap), but the company IT was adamant on bringing anything in-house that could be brought in-house.
Github is great, but there are very few situations in which Github Enterprise really makes sense, IMO.
GE gives us far more control, far more logging and auditing (which is the real key), as well as nice things like LDAP authentication that make adding and removing users from the system far, far easier to manage. There are real reasons to use it besides just wanting things in house, although for a software company who needs to keep their software secure you shouldn't use anything except Github Enterprise. We all saw the bug that happened just a few months ago- who knows how many people were using that maliciously before it was made public.
I will say though, there have been a ton of improvements in Github Enterprise. We rejected it after getting a trial six months ago, and gave the sales team a huge list of problems (it was kind of disgusting, actually). Since then they've actually addressed the vast majority of our list (certainly all of the high priority things), which prompted us to look at it again. We're pretty happy with that decision.
That being said, if you're too cheap to buy licenses for all of your staff then you shouldn't use the thing. That's not a Github Enterprise specific issue though.
Because they'd rather have you using the hosted platform instead of having to support enterprise customers. There's a very steep support side when you sell something as "enterprise."
We've used gitorious as well, but due to several problems we've now switched to a GitHub organization and Gitlab. Much more happy this way in general, but the team management options for GitHub are lacking. Purely going for the Gitlab route would've probably worked out better. (We have around 50 people with Github accounts now and some of them are changing teams frequently.)
I believe the biggest complaint I keep hearing about GitHub:Enterprise is it's crappy search functionality. I think a lot of developers want to be able to search the code easily, and Github:E seems to be mediocre at it.
They should seriously consider using OpenGrok. It's a fantastic open source code browser / searching tool that supports a variety of languages. It's also released under an OSI-approved open source license.
We could have easily paid $300/yr ($25/mo) instead if we just used the normal Github site and had a better experience (they were constantly shifting things around to avoid the 20 user cap), but the company IT was adamant on bringing anything in-house that could be brought in-house.
Github is great, but there are very few situations in which Github Enterprise really makes sense, IMO.