Merb was created by as a workaround for a very early and specific performance issue in Rails: uploading photos efficiently. Since then, it's become a full framework that had many wondering why Engine Yard was supporting a Rails competitor. We always felt that Merb was complimentary to Rails: an extra tool in your Rails toolkit. Regardless, it has become increasing clear that Rails and Merb were on a collision course that was leading to a schism in the once unified community of Ruby developers. We're delighted that the teams are working together to avoid such a schism, and as such we fully support the merger of the teams and code bases.
Engine Yard was founded as a Ruby on Rails deployment company. Nearly every one of our 400+ customers uses Ruby on Rails! Perhaps the thing that makes me happiest about this announcement is that we will now directly support the Ruby on Rails framework by placing existing Merb resources into directly improving Ruby on Rails. We find it very fitting that we'll now directly support the framework that has supported Engine Yard's very existence!
Enormous kudos must be bestowed upon the Ruby on Rails and Merb core teams for agreeing to work together for the betterment of the community. Now, rather than discuss the relative advantages of Rails -vs- Merb, we can get back to the real business of changing the world, one developer at a time, by freeing them from the shackles of less efficient development environments.