Consumer POV
It's piss awful.
However that's not necessarily down to the technology, but the implementation - however if you can make it that shite then there's something wrong with the tech too IMHO.
We're an MSP that's focuses mainly on MS tech. Our upstream network partner (we resell their products as a boutique ISP) that we have colo with offered us the opportunity to be the first client on their new OpenStack environment.
Hours spent getting drivers for Windows 2008 R2 and injecting them in. Had the provider reboot our instance a few times by mistake. Advised there's no firewall between the instance and our colo other than our main colo firewall. Total, utter bollocks. Again, hours spent trying to fix an issue after their accidentially reset the config on this non-existant firewall so turning it one-way (that passed ICMP both ways just to really throw me off!) which totally screwed up our Exchange DAG that spanned into the OpenStack instance.
And the performance... my $God. We've actually given up trying to backup from the OpenStack instance now entirely. The read performance is terrible. VSS backup of Exchange on the VM on our HyperV colo - < hour. OpenStack, gets to >5 hours and then times out. Apparently they have a "Ceph" cluster with SSD's and excellent IOPS - but I'm clearly not seeing it.
Sorry, but I've rolled my own vSphere (3.5 - 5.5) and HyperV (2008R2 - 2012 R2) as well as used Azure and vCloud Air and OpenStack, in the way our provider configured it is just a dead duck. Nothing good at all came from us using it.
We've since brought a new bit of tin and are in the process of rebuilding the instances we have on OpenStack so we can decommission.
Appreciate that this is probably down to how it's been implemented - but these guys aren't spanners. They've FOSS nuts who develop their own Linux based firewall and run as an ISP. All Linux nuts.
Sure, they've probably messed things up - but I can't remember a time when I deployed VMWare of Microsoft products for the first time and things ended up being so... well shit.
Sure if you're a massive company with a lot of FOSS resource you can dedicate you can probably craft your own cloudy stack and OpenStack is the best way of doing this.
Everyone else, seriously, I'd recommend paying HP to use Helion or a similar provider, or just use Microsoft's Azure Stack onpremise or use VMWare's vSphere stack instead.
After the rest of the Infrastructure team here started calling it OpenShat I think I decided we weren't going to look into it any futher...