Yes, I've worked with a few of those datacenters. A few examples:
- Recently had to purchase new servers, because of signed contracts the only servers we were allowed to purchase and put in the datacenter were four years old and technically EOF.
- Firewall changes, AD changes, provisioning a VM, etc. are 48 hour turnaround. Purchasing new hardware requires 4-6 weeks.
- Had an intermittent issue with their edge firewall, it'd slow certain connections to a crawl and eventually they'd timeout. Took six months to fix it, for the first three months they told us it wasn't their fault (turning off their deep packet inspection ended up fixing it).
I still remember when we opened the first ticket about it, and the reply was "no other customers are experiencing problems" and it was closed.
That's just a few examples of how painful it can be. To give you the other side of the coin, having worked with an enterprise contract in AWS, we were having an intermittent issue with DNS resolving failing for a few seconds every few days. They put an engineer on it full time till they found the problem (we misconfigured it), and it didn't cost us anything more than the enterprise support. I was actually shocked they'd invest that much on such a vague issue.
Yes AWS is expensive, but you're getting world class engineering proven at scale, and access to some very smart/motivated people to support it (and they have access to the teams who built it, when they can't solve it). I don't think I'd ever choose managed datacenter over AWS/GCP/Azure/etc. Either do it in-house where there's accountability, or use cloud providers who have proven they're competency.
To be clear, I'm talking about VPC/EC2/etc. I can't really discuss a lot of their higher level and newer managed services; they either weren't as good, or I haven't tried them. But the bedrock these clouds are built on is solid, and that's worth paying good money for.