If I may ask a few questions:
- Are they charged the same as external customers or do they get a 'wholesale' rate?
- As internal clients, do they run under the same conditions as external clients? Or is there a shared internal server pool that they use?
- Do they get any say in the hardware or low-level configuration of the systems they use? (ie. if someone needs ultra low latency or more storage, can they just ask Joe down the hall for a machine on a more lightly loaded network, or with bunch more RAM, for the week?)
- Do they have the same type of performance constraints as the ones encountered by gitlab?
I feel like most of the reason to use cloud services is when you have little idea what your actual requirements are, and need the ability to scale fast in both directions. Once you're established and have a fairly predictable workload, it makes more sense to move your hosting in-house.