With all good companies, there are serious pitfalls that will ultimately knock down the average uptime of services. Yesterday, Google experienced a major outage in their email services. Companies will usually downplay the impact of their outages but this time it was pretty apparent they had a major breakdown with email delivery. You can read more about it here. What did we learn from this outage? There is no silver bullet when it comes to outsourcing some or all of your infrastructure. The question you should think about is whether or not you can do it better than someone else. If you want an on-premise solution because you will have greater control over your data and want custom settings, be prepared to face the consequences of a server meltdown. If you want to outsource your email, be prepared to face the consequences of a server meltdown as well. On the bright side, you're not the one fixing the problem for the latter. If I had to choose between on premise vs off premises (managed services/cloud), I'll go with off premise just because I won't be on the hook if email goes down. Do the math, one IT guy vs dozens of IT guys at Google. I'd rather let someone else deal with it for a change.