Managed Security Service Providers - Stories of Success

I read a *LOT* of horror stories about managed security companies (MSSPs) that suck and do nothing. I'd like to hear some stories about MSSPs (or MSP if you prefer that nomenclature) that do good work. I am considering MSSPs right now for a project I am working on.

* What does your MSSP do that you really like?
* Why did you select them?
* Did you have a different MSSP? Why was the one you have better?
* …

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