It all depends on what the SLA says, but hypothetically, if they are down for 24 hours a year, that's 99.7% uptime, which isn't terrible.<p>Heroku had a 1-2 hour outage the week after we switched an app there last year. My boss was freaking out, cursing about how they were unreliable, etc, neglecting the following:<p>1. The timing was unfortunate, but that was the first outage in months.<p>2. We had had multiple outages on our Rackspace box that were our own fault, due to bad server management.<p>In the long term you're likely better on Heroku, for small companies at least.