[atmosx]

Is this for a commercial service? If yes, then I'd say at the beginning go with Heroku (or Modulus), concentrate on software and leave the DevOps/Sys-admin for later. If your project starts generating enough cash/traffic then either stay with Heroku (if this is a 1-guy venture) or go with a VPS if you have time or can find someone who will setup and manage all the rest (security, updates, backups, etc.).

[yatoomy]

Modulus does auto scaling and load balancing between their mini server instances. The fact that I can get 3-4x more servos free from Modulus (because of that program) makes it appealing. Also features that would save costs from other SaaS solutions ex. they roll similar functionality of pagerduty into it