One of the slides shows "Rails is still the best choice for entire classes of apps."<p>"Best" is of course usually subjective, and this could spawn huge internet arguments back and forth about the relative merits of various solutions. But I think there's perhaps an objective argument to be made that this isn't true now, and won't be true with Rails 5 and beyond.<p>I own a web + mobile app dev shop (Infinite Red). Our background is Rails, and some on our team have been using Rails since pre-1.0 (Steve Kellock, for example wrote the first Rails guides, and his name still appears on the website). We have loved Rails (and Ruby) for a long time.<p>But the concurrency and scalability difficulty of Rails isn't just an opinion. As we've built larger and larger applications on Rails, the amount of effort put into making Rails scale gets disproportionately high. Not to mention server costs.<p>Yes, it's totally possible to scale Rails. No, not every Rails app needs to scale to Twitter-level. We get that; we've been doing both for years.<p>When we discovered Elixir/Phoenix [cue the groans, sorry] it felt like we kept the magic of Ruby on Rails while (in a single stroke) we also made a giant leap forward in concurrency, scale, and reliability. In my opinion, this is the direction the Rails community would be better off going. We felt so strongly about this that my partner Ken Miller wrote a piece titled "Phoenix is Rails 5". <a href="https://shift.infinite.red/phoenix-is-rails-5-f6d28e57395#.1z9pas7co" rel="nofollow">https://shift.infinite.red/phoenix-is-rails-5-f6d28e57395#.1...</a><p>We don't need Ruby on Rails to be great again. It's done its job and we're all better for it and grateful for it. We don't have to become Node.js developers and abandon all the things we love about Ruby and Rails. We have a better alternative: Elixir/Phoenix.