I have been using Heroku since last 3-4 years and now I have clients wanted to use openshift for their ruby application deploy.
I know heroku features and new to openshift. I know few features of openshift like gears, cartridges, marketplace etc.
Both use aws for online service and same git deployment strategy.
I wanted to know what is the advanteges of openshift over heroku to deploy ruby applications?
I would research the features of each platform and compare the features that are important to you. I would also try searching for "OpenShift vs. Heroku" which will return many articles contrasting these two platforms.
Honestly they are both good services, so which one you use will depend on what your requirements are. For example you can run almost any database on OpenShift, but need to use PostgreSQL or a third party database service with Heroku. You get more resources for free with OpenShift.
Your question is really too broad, not programming related, and any answers are going to be opinion-based.
