I've had a great experience with prgmr.com, even when asking them possibly-stupid questions about my configuration. If you can get to one domain but not others on a VPS account, it's likely not the VPS provider's fault...
Yeah, was gonna say - a VPS provider's job is to make sure you have a running box and a good pipe to it. This is almost surely a configuration issue on the VPS and not the provider's fault.
I certainly understand your frustration, but I think the heart of the matter is that prgmr may be inappropriate for your needs rather than "prgmr is unreliable." I feel like they're quite clear about the fact that they're not for everyone.
If you need high-availability, you can buy 2x prgmr nodes at different locations, for the same cost as most other VPS providers, and you'll get MUCH better reliability that linode or such.. But perhaps you should clarify that it was your fault in your post.. I don't recall ever seeing any long outages..
Also, Prgmr likely runs monitoring software to identify when servers go offline, in which case, they may be able to respond to true outages sometimes the moment they happen.
But even with that said, I've found their support to be great. They've helped me with a fair share of configuration issues, even though that's well beyond what I thought they offered.
If you have had good support, that's fair enough. I haven't and complaining on a public forum was my last resort to get any attention or help. The fact that no one from prgmr has yet responded to this thread is telling. It seems that one gets such bad customer service either from really small teams or giants like Google. I am not scared to call businesses out on poor service.
The response time for emails isn't great, but server outages seem to get fixed pretty quickly. Furthermore, I think you need to accept in your case, that it probably wasn't a hardware issue....