I can confirm this, self-hosted is incredibly fast - you'll wonder how you ever used gitlab.com or github.com for that matter. It's as fast as it is for me to push to a locally running git server to be honest.
As a side note: GitHub.com is hosted on Azure and that says a lot, at risk of sounding like a zealot - I have quite a bit experience with apps including office365 hosted on Azure and that platform has more than its share of problems internally, problem is that it's a bit black box that's run by one of the least transparent companies I've worked with, let's just say there are a lot of internal engineering problems especially around networking (DNS especially) and storage. While I'm sure gitlab could throw more resources at their instances they're probably limited by costs / going above what is offered for HN startups to try to lock them into the platform and that may not help given the aforementioned internal platform issues.
Rest assured, self hosting an instance for say 50-100 developers does not require much 'grunt' at all as long as your platform is stable and properly managed which I don't believe should be at all hard in 2016 assuming you have half decent systems engineers or use a decent hosted platform.
