I'm using Google Apps for your Domain because of reliability. I've upgraded to the premium edition for peace of mind with a 99.9% uptime guarantee.
Why then was the mail service (smtp/pop and web) down for 5-6 hours yesterday? This is the only response received from google:
Hello,Today, although pop and web access is working, smtp is not. Is anyone else having similar issues?
A number of Gmail users are having some difficulty accessing and sending mail, and we are working as quickly as we can to resolve the problem. Some Google Apps accounts are also affected, including one or more of the accounts on your domain. We know how important Gmail is to our users, so we take issues like this very seriously, and we encourage organizations who are having technical difficulty of any kind with Google Apps to contact the Google Apps Support team through the Google Apps Help Center (http://www.google.com/support/a/).
We apologize for any inconvenience, and we will update you as new information becomes available.
The Google Apps Team