I'd been using Heroku since forever, but bailed on them for a high traffic app last year (Olympics related) due to poor performance once we hit a certain load (

I'd been using Heroku since forever, but bailed on them for a high traffic app last year (Olympics related) due to poor performance once we hit a certain load (adding dynos made very little difference). We were paying for their (new at the time) critical app support, and I brought up that it appears to be failing at a routing level continuously. And this was with a Sinatra app served by Unicorn (which at the time at least was considered unsupported). We went with a metal cluster setup and everything ran super smooth. I never did figure out what the problem was with Heroku though and this article has been a very illuminating read.