One thing I would like to say is that the development experience with Ruby/Rails is by far the best out of all of these languages. By FAR.
The way you can start a project in a second is amazing, the TDD experience and Rspec integration with Rails is simply mind blowing comparing to anything else.
Express might be 100% faster than Rails but it will take you 5 days just to get something running vs what you can do with Rails in a matter of minutes. From Authentication to Authorization and all the community around these.
Regarding the fast/slow it's simply bull-crarp, seriously. It DOES NOT matter for 99% of us. It simply doesn't.
Most of the slowness you are experiencing in Rails and Ruby apps is by doing poor engineering, not by Rails or Ruby itself. Big Surprise... If you query 1000 rows and bind them to the controller things will be slow.
There are things that are natively slower, JSON parsing and marshaling for example is one. It's much slower than Go for example but it's so much easier and for 99% of us, this is what matters.
I don't get the hate that Ruby and Rails are getting. Really don't.