Interesting. I was just considering them over AWS for hosting. Current users, how reliable is Heroku? While I appreciate openess, looking over that status page does not inspire a lot of confidence.
At the size of Heroku, the probability of a server outage per day is actually quite high. As long as the errors are just "one of our machines has gone down", its an interesting information for everyone on the machine, but it doesn't say a lot about the reliability at all.
For ref, the heroku app is rails, 2x dynos and a shared DB with minimal traffic. The others are PHP/apache apps, one using RDS, on plain EC2.
Heroku is at least 5 layers extra to go wrong on top of EC2. On the one hand I feel that each layer adds to the probability of failure. But I'd hope that one of the benefits of Heroku would be extra redundancy and failure handling, though my limited personal experience hasn't been that way so far.
EDIT: Regarding openness, I certainly feel that every single outage is admitted by Heroku, whereas I feel Amazon's status page has not listed a few outages I've suffered. Again personal feeling, not evidence.
When Heroku has issues during working hours, their support is great - you can pretty easily be put in contact with an engineer or a product manager. The catch here is that there doesn't appear to be any guaranteed response time to any tickets (my urgent ticket (everything is on fire) from Sunday was accepted Monday morning).
Amazon on the other hand is quite opaque - SQS/SimpleDB, for example, went down today for a few minutes (as in the service endpoints told us as such), but there wasn't a peep on the AWS status dashboard.
May not be related, but if you're on Cedar you'll want to make sure that Pingdom is sending a GET request. I've seen a few uptime monitoring services that send HEAD requests, these worked on Aspen/Bamboo as nginx would translate them on the way through.
I've no idea why these services didn't report that my apps were permanently down :(
