Edit: I don't to sound like a contrarian or prove anyone wrong or something. I'm certainly not the person to do that. I just read some of the comments here that

Edit: I don't to sound like a contrarian or prove anyone wrong or something. I'm certainly not the person to do that. I just read some of the comments here that seem to overestimate the distance between the two stacks in the article. The stacks in the article aren't very different and few of the comments here seem to reflect that. Erb vs Haml? Not much of a switching cost, especially since they can be used in the same project without sweat. One is HTML with <% %> tags, the other is a less familiar nested syntax to generate markup. Mysql vs Postgres? For most CRUD, the same Active Record queries pretty much work, and the shortcomings are due to Active Record being underwhelming compared to its alternatives. Someone that cargo cults Mysql vs Postgres probably isn't locking their schema/queries into one or the other because staying close to Active Record doesn't really let you do that. Minitest vs Rspec? Tests would be annoying to rewrite, but testing layer differences don't really distinguish a Rails app. Especially since you can write almost line for line equivalent code in Minitest and Rspec. Fat models & skinny controllers vs skinny models&controllers + service layer? Here's the first real difference on the list because it actually changes the design of the system, not some ancillary component. So, > How many parts of Rails can you swap out before it stops being Rails? I think we can stow this question away until there are more divergent, popular alternatives to the default stack which I'm looking forward to in time. For instance, I think we will start seeing more deliberate functional designs that decouple models from Rails (to make testing not suck, for one). And I wish Active Record alternatives were far more popular in the Rails community.