Any real datacenter that is not in someones basement but an actual datacenter location will be reliable. They want you to remain their clients. I think you need to start thinking more along the lines of where do you want it to be located and possibly what price range you are looking for.
The biggest thing you want to make sure is that it's Tier 3+ has 24/7 support onsite and don't charge you for reboots and basic tasks.
At the end of the day anything can happen and there can be some downtime, however we've noticed over the years remote hands is one major factor that many miss.
It's useless being in a remote data center if they don't have staff 24/7 we see this a lot in New York people requesting remote hands from us because their data center is lights out with no techs onsite.
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